So many have ask about HR (Heart Rate) based training benefits (as opposed to pace based training) that I decided to write this overview. The questions are reasonable, given that HR training (and racing) is more involved. That is why I didn't do it for a while. I wish I had. This document tells why and how.
Near the bottom I added terms (e.g. LT, BPM, etc.) that may help, and data from my own running so you can understand the context. (I didn't want to clutter this area.)
Don't judge the benefits of HR by a person's speed. You'll find fast and slow on both sides of the camp. Judge by whether this makes sense for you and your life. Having said that, there's no doubt in my mind that HR governed training is the fastest way to improve... It's difficult to CONSISTENTLY FEEL (without HR) how close you are to what you should be doing. HR is not a perfect metric for effort, but it is quite good, and I submit it's far better than feel.
Although I had been curious about HR training, the real motivation initially came from running an enormous hill almost daily. My paces ranged from sub-6 MPM (minutes per mile) to 13 MPM. I could get an average pace, but it was difficult to know how close I was to the best effort level. Enter HR governed training.
BOTTOM LINE: When using pace or going by feel, I was too often below or above the optimal effort. While not perfect, heart rate (HR) is the most reliable method of keeping me in the most ideal zone (not too fast, not too slow) for the type of run I'm doing. IN A RACE: HR does the same thing... it keeps me closest to my optimal performance, spreading the effort evenly over a course. It packs the most training into the least amount of time.
|Comparing to Others
This depends a great deal on what you're trying to compare. It's easy to say who's faster in a specific race (finish time is all you need). Yet, one person might be running a tough race, and the other might be doing an easy race. The hard thing to compare is effort, and ability to run. Neither pace nor time tells you those things.
EFFORT: There will always be difficulty in comparing because performance depends on many things. The best method to compare runs is: find comparable conditions, then use % HRR. While it will still vary over time (and between athletes) it's the best way and will be close. You can also attempt to only allow ONE thing to vary. Find the same conditions, and hold HRR constant, then compare pace. OR find the same conditions, and hold pace constant, then compare HRR. This is the most comparable.
|The next best is % MaxHR (percentage of Maximum Heart Rate). It's not as good because it does not account for the resting heart rate, which varies a lot from person to person AND within the same person over time.
BPM (Beats Per Minute) varies dramatically across athletes, so do not use that to compare performance.
EXAMPLE: I'll compare my 70% HRR with two friends' same HRR so we are expending roughly the same level of personal effort.
- My current 70% HRR is at 151 BPM
- Friend 1 has a 70% HRR of 138 BPM
- Friend 2 has a 70% HRR of 146 BPM
This cannot tell you who is faster. If we all hold this 70% HRR for 12 miles, here's what might happen... and THIS tells you who is faster:
- At 70% HRR, My pace might be around 7:50 miles/minute
- At 70% HRR, Friend 1 might have a pace of 6:40 miles/minute << Fastest
- At 70% HRR, Friend 2 might have a pace of 8:25 miles/minute
You could also hold Pace constant. The resulting lowest HRR would likely be the fastest.
HR HELPS FOCUS ON EVEN EFFORT: With small variances, HR training can reflect (and encourage) real consistency in effort spent, both up and down those hills (it also works with wind, heat, heavier winter clothing, etc.). HR, to a large degree, adjusts for all of those kinds of conditions. When I'm running at my Long Run (LR) effort level, I might target 151 BPM (which is currently about 70% of HRR). My pace may be 13 minutes per mile up a hill, or sub-6 minutes per mile down the other side, but my effort is fairly consistent as measured by my HR of 151 (~70% HRR). (Caveat: I usually allow about 5-6 BPM higher up hills.) HR helps reduce both over taxing and under performing. This has been a big help in other conditions too. Even when average pace is ruined by wind, HR based training helps you pick the right effort level for your current condition. Yes, you can blast hard into the wind and maintain a specific pace, but if done for an extended time, you may be overdoing this specific run, requiring longer recovery, or hurting your later performance in a race. On hills, HR training helps you slow down a bit (people tend to push too hard, fearful of not making up the time.. see the excellent article in REFERENCES about aidedness). BUT FAIR WARNING: while HR training takes out the peak killer moments present in the uphills, it also adds sustained tougher flats and downhills. Summary: HR avoids overdoing it uphills and going too slowly elsewhere (for your current conditioning).
|Hill Running Side Note
|For rolling hills, you can (and should) gain back most of the energy spent on the uphill when you are going down the hill (if you can train on hills). HR is Fantastic at helping you do this. BUT, be warned... downhill running can tear your muscles up if you are not accustomed to it. If you do not train on hills, then, in a race, be more conservative downhill or you may, WITHOUT REALIZING IT, tear up your muscles and several miles later, blow the race.
One additional nice thing about HR is that there is an automatic adjustment... for any target HR, as you become more fit, you will run faster at that HR. From another angle: I go out every morning, not knowing my pace, but I know my target heart rate. You'll notice your speed increasing over time for the same target HR (when under similar conditions). This is just a great thing to see happening.
For races, HR eliminates the need to predict your pace and matches your current level of fitness wherever that happens to be. This is really a big plus... it helps you stay closer to your best level of effort, maximizing your training (and race results).
|A Test of Feel Vs. HR Governance
|I once did a test to see how close I could stay at a given HR just going by feel. I ignored my watch for my flat MLR 13 and attempted to FEEL my MLR effort (a 151 HR). Note: this was on a fairly flat circuit so consistency should have been easily achieved. The result was BIG variance in my heart rate (141 - 159 - 145). I did average 150, so that might have appeared to be good at first. But no! Seeing the splits proved otherwise. The variance took me away from ideal conditioning effort. It was progressive (upward) until the middle, then the heart rate tapered again (I was unaware of this). I FELT like I was running consistently the entire time, but the profile of the run looks like a newbie (except for the newbie's typical blast at the beginning). Average pace: 7:59.. solid, but could have been faster and NOT gone out of the target HR range. IN CONTRAST: A Prior HR guided run saw 152 average but with much more progressive consistency (even though this run was in a VERY hilly area).. increased slowly ranging from 147 to 157 (full disclosure, the last 1/4 mile I blasted a little and hit 164 but I don't count that). Average pace: 8:10.. Much better given the 600+ foot ascent and a matching decent. MY CONCLUSION: Monitoring my heart rate is keeping me in a narrower and more beneficial effort range throughout my run, maximizing my conditioning. This consistency showed up in my first two HR governed races (Tupelo and Pensacola) too (see the graphs in each).
I started doing HR training near the end of 2011, preparing for Boston 2012. Unfortunately, my HR belt battery died the morning of the Boston race (4/16/2012), so I had to go by feel and pace. But the training was all HR. Given the heat (~85 - 87F and sunny at the finish), I was happy with a 3:35:32... about +9 minutes from my PR at the time. (My PR had been ~3:26.) My Tupelo marathon was the first one in which I could run by HR. This was also the first marathon in which I did not fade to any significant degree. I had a GREAT EVEN EFFORT that was made possible by HR governance. Here's the graph.
% of Heart Rate Reserve - for Tupelo (hotter)
|% HRR is red line - Elevation is the beige graph
On November 11, 2012 I raced The Pensacola Marathon (see the race report), with much cooler temperatures and produced a similar HR graph using HR governing. I came in at 3:15:38 (a PR enabled by cooler temps) and governed the race by HR (I stayed a bit more conservative in the first half than I could have).
% of Heart Rate Reserve - for Pensacola (cooler)
|% HRR is red line - Elevation is the beige graph
HERE'S A BIG POINT: HR running allows you to do what you can, given the conditions, even when you don't know what you can do. I wasn't sure what pace I could attain in Pensacola but I did not govern by pace... I governed by heart rate, keeping my HR near 78% HRR (164 BPM for me). This target HR was discovered by picking the correct HR levels in my types of training runs, then knowing my training "Marathon Pace" heart rate range. (..and how deeply I could go in the range. More on that below.) My heart rate, in the cooler temps, automatically translated to a faster pace. (Other than the early calibration I had to do at the hotter Tupelo race, this was all automatic.) This Pensacola run proved (in the first few miles) that my training HR levels worked in this race. I needed nothing else... watch HR and run efficiently. I kept my HR in the low 160's in the first half, then allowed it to climb to the higher 160's in the 2nd half. The faster pace was the result of HR keeping me close to my capabilities, regardless of what I thought I could or could not do.
I want ALL my races to yield an HR graph with these kinds of results, showing a very even effort. I'm very excited about heart rate training and will never go back until I just don't care how fast I am.
|HOT vs. COOL - Heart Rate Racing and Tempurature
In training, my "marathon pace" or effort level is around 77% of HRR (Heart Rate Reserve) which is 162-163 BPM for me. But tempuratures do affect HR. Heat elevates HR for the same effort. This is in part because the heart has to pump extra to help cool in addition to feeding muscles. For a hot race, one must be ready to calibrate for the conditions.
THE PRIOR RACE: I had only run one race using HR (heart rate) governing (Tupelo) and it was hot (75 degrees - 97% humidity). My average HR in the Tupelo race was 82% of my HRR (Heart Rate Reserve) which is 170 BPM for me. This was above my average for training (in fairly similar conditions). In the first 5 miles of Tupelo, I had to calibrate to the roughly 168 BPM I was seeing, based on pace and how I felt. So for the first half, I targeted high 160's and then past 170 after that. It worked well given the heat.
SO FOR MY NEXT RACE (PENSACOLA): This race started at 58 degrees and I had to decide (within the first few miles) whether I should target 168 for the first half (like Tupelo) or ~162 (my Marathon Pace effort in training). I warmed up first (first few miles) then watched how my heart reacted. It became clear that my training for marathon effort (MP for Pfitz' followers) was right on target... so I pushed for around 162 in the first part, then went a bit higher (about 166) in the last half or so. I averaged 164 throughout the race. The cooler temps made this race align well with my training.
If you care about speed, then care about HRR training. The problem with comparing two people's actual performance potential is it doesn't account for genetics, gender, climate of training OR races, etc. What matters is whether you will progress faster with HR training vs pace or feel training. I hope I've convinced you that HR training/racing keeps you near what you can do (avoiding too far below or above... either of which ruins a training session or race). I'll talk about how to do this now.
Other than the MaxHR test (and needing an HR measuring device) it is not hard. Yet, that MaxHR test is hard. There are calculations, but I can provide a spreadsheet to do all those calculations for you.
Using my spreadsheet, I see my printed goal BPM for each type of run (my spreadsheet helps provide a single number as my basic HR target for that type of run... I start with a heart rate under that number and end just over it (by a few BPM each side). It's very simple.
For example, my target for LR (and MLR) is 151 BPM... when I hit near that (maybe 147) I consider myself to be warmed-up and my MLR has started (although I sometimes start at an even mile boundary.. no big deal either way). My HR (with a fairly consistent effort) will climb slowly through the run. Near the end I allow it to hit maybe 155 (could be higher if I blast at the end).
I sometimes don't need to look at my watch. When I don't want to, I don't, and just run. But often I do, especially when I'm going uphill, downhill or in wind, etc. My "feel" is too inconsistent in those conditions. But I often sanity check my HR periodically even on a flat run. Usually, I'm OK, but every now and then I adjust. I like to assure a slowly increasing effort over the core miles (after warm-up and before cool-down).
Converting to HR is not hard once the HRmax test is done (but it is a tough run).
|Quick Method to Just Get Started
If you want a low-investment way to start HR based training, just wear your HR monitor for about 5 of each of the kinds of runs you do (e.g. 5 LR, 5 MP and 5 LT) in flat and reasonably cool conditions. See what the average is for each... that'll give you a reasonable feel for what's right for each of those. It is much better to find the MaxHR, but can still benefit from this quick way.
For those not used to running (new, or not run in a long time, etc.) there are a few things to keep in mind.
- Your Resting HR will change as you become more fit. (Even your Max HR can change, but it tends to not change, or not as much). Thus, your HRR (Heart Rate Reserve) will also change.
- Your HR during any given run will be fairly high compared to what it will be when you are more fit.
I recommend that you not worry about measuring your Max HR until you have been maintaining a steady training program for a little while (although it will not hurt to measure it). I would measure your resting heart rate because that will help you measure fitness changes. Use your HR monitor and begin seeing where your HR is during different effort levels. Keep the running easy for a while. After 4-12 weeks of consistent running, your HR will become more consistent (for the same conditions). Then it would be good to measuring Max HR then use the spreadsheet below to learn more about your specific ranges.
You'll need your Resting HR (easy) and your Max HR (tough).
RESTING HR: Take it in the morning when laying down and having just woken up... do that for a few mornings in a row and take the lowest rate that you find. Use that for your HRR calculations.
The hardest part is getting that Max HR number. If you have tracked HR data for a 5k (or close to that distance) then you may have a reasonable estimate already. That's where my best Max HR tests are from. But there are other ways.
ROUGH ESTIMATES: While I don't trust calculated maximum heart rate formulas, one of the formulas is 220-age, so with that, mine would be 220-52 or 168. Thus, I don't trust it... mine is actually 198. You can see http://www.brianmac.co.uk/maxhr.htm for other max HR calculations, but I would not put a lot of stock in any of them. Yet, if this is how you want to start, do it. You'll just adjust how far you go INTO each range (see more below on that).
The HRmax is a hard test. That's the biggest hurdle and will stop many people. I'd use estimates before giving up. Once you get a reasonable number for your body, you will have a great tool to increase performance greatly by using HR readings to govern your basic effort level, keeping you consistently closer to the ideal level of effort, and maximizing your training benefits.
BAD TEST: Any single blast in isolation, even at a sustained top speed, won't do it. If you blast without fully warming up (and I mean really fully, not a normal warm-up) then your body is not "rev'ed up"... your capillaries are not dilated, your muscles are not ready, etc. You absolutely cannot reach your MaxHR no matter how hard you try, until you are fully warm. If you run too much before the test, you'll be too tired.
GOOD TEST VARIES BY PERSON: Some can warm up (e.g. a normal run) then do three blasts (maybe uphill) with short rests in between and get a good reading. Many of us (me included) cannot even do it that quickly. I have to run at LT speeds for at least a couple miles (after a good progressive warm-up) THEN have a short slow-down, and then mad blast for a few minutes. Nothing else works for me. I've seen this happen in three separate 5k runs and in a 4 mile run. (For some, the way I do it may make them too tired to hit their max.)
NOTE: This is optional. I believe it to be the best thing to do, but one can be very successful with HR training WITHOUT doing this. Just pick a point in the running categories and go with it. But if you want to calibrate all your runs based on your current level of ability, this section will help you do that.
Each Pfitz run type has a range of HRR percent. They even overlap. How far into that range should your target heart rate be? I originally asked this question because I was doing LR runs at LT levels, yet it was still technically within the LR range. But too high of an effort (even if you can do it) may hurt future runs because of the needed recovery time (e.g. a "too hard" LT/Tempo today can hurt the next 12 miler, leaving you running under your potential in this next run). So I wanted to know, for example, how far into my LR range (or any other range) should I go? Here's my answer.
Use the hardest extended run type, LT, as a calibration for how "deep" you go into the other run types (e.g. LR and others). You could start your LT at the lower end and work up. You can also borrow from your current knowledge of pace, etc. Settle on an LT effort that seems right (should require a strong effort but maintainable on a day with normal conditions for you). Measure the average BPM on that run. That becomes your single LT target. Figure out how deep into the LT range that chosen number is (use my spreadsheet if you wish). For me, the chosen LT heart rate was 168... difficult, but once fully warmed up, doable. Pfitz's HRR% range for LT is 77-88%. For me, 168 is about 81%... which is about 32% into the Pfitz LT range. So 32% became my chosen effort level for ALL workout ranges (which gave me these targets: 168 for LT, 162 for MP, 151 for LR). So again, the LT target can be used to determine (calibrate) other types of runs... this helps assure that I'm not going too fast or too slow.
|Consequence of Too Much Effort
|Before that approach, I was doing LR at around 78%... way too fast for my conditioning, which would require LONG recovery times, and negatively affect later runs. This drove me to pick a more appropriate pace that I can maintain AND quickly recover.
At some point, when I've improved even more, I'll go deeper into my LT range (and similarly in my other ranges too, e.g. LR and MP). But this kind of adjustment is not needed very often. This level has worked for 2-3 years. An adjustment is only needed as you run LT and believe you should be running slightly faster. That's when you increase your HR, see how far into LT range that is, then adjust the other ranges equivalently (the link below to the spreadsheet will help you do that for Pfitz' ranges).
In a RACE, your target HR may change... depending on the conditions (mine Tupelo example was caused by heat) I experienced about a 5-15 BPM increase for very similar conditions (race average was 6 BPM higher compared to a more ideal race tempurature). Yet I was able to maintain this higher HR in Tupelo. I could not have maintained that higher HR in Pensacola... and didn't need to do so. The cooler temps (thus lower HR) at Pensacola yielded a much faster time. You can see this effect referenced in Pfitzinger's article: http://pfitzinger.com/labreports/hrmpitfalls.shtml and I was very happy that I had read that before experiencing it, so I could adjust my running during the race.
|How I use HR in a Marathon
The miles are a rough estimate, and some of this changes but this is a basic layout that is repeated every race, since my start with HR governed training and racing. While I know the time I'd like to get, I use HR to govern my effort, not my pace. On a hot day, it's slower than I want. In ideal conditions, health, etc., it's faster than expected.
Here's how I use it:
Miles 0-6: At first, I monitor how I feel, my pace and my HR. After a thorough warm-up, and around mile 5 (or 6), I lock onto a target HR (this is based on what I've learned from training and a live adjustment on this race in context. The target can be adjusted later but often there's no need), starting 3 or 4 BPM below the target.
About miles 6-16: HR largely governs. I slowly increase HR to the target as I feel it's reasonable and sustainable.
Around 17-23: I hold to my HR levels more strictly (0-2 BPM above the target which was chosen around mile 5 or 6).
AFTER that (24-finish): I segue to doing what I can, allowing significant increase in HR as I can. Sometimes I finish much faster than prior sections. Other times, I have little left and only feel like I'm going faster. But I've given it all I can, and the results are usually quite good, and more consistent than I did in the past.
SO FAR, I've not had any "blow ups" in a race that is HR governed because HR helps me catch that and adjust.
ADJUSTING FOR A RACE: In a race with good conditions, something in your MP range should work (practice runs using HR will help you know this in advance). But be ready in case you need an adjustment for out-of-the-ordinary conditions. I start with a possible target HR based on my MP effort training runs. Then I test it in the first few miles (could be up to 5 or 6 miles) of a race watching both pace and HR to find a high but maintainable effort. That HR measured effort becomes the target for the race, determining my effort throughout the race (increasing it slowly over the course of the race). Whatever pace that yields is what I do, up hill (slow), flat (fast - for me) and down hill (fast). I don't specifically target a pace... so I often say "effort." In my first HR governed race (hot) I saw that I had to pick a higher HR than I expected. In my second HR governed race (good weather) I quickly saw that my typical MP rate was right for the conditions so no adjustment was needed. Here are those two examples:
- EXAMPLE OF ELEVATED RACE HR: In my first HR governed race (Tupelo), I could have targeted 162 BPM, my typical HR target for MP training runs. But during the first 5 miles or so I saw my heart rate hitting around 168 in conditions that would normally yield around 155. So during the run, I picked 168 as my "race target HR"... I was able to hold that (elevating it near the end) see the HR graph above.
- EXAMPLE OF NON-ELEVATED RACE HR: In my second HR governed race (Pensacola) was much cooler and my HR was down at my training levels this time. In the first 3-4 miles, I saw that my HR levels in my training runs (162 BPM) would match this race with no adjustments (because of much better conditions). This automatically yielded a much faster time, even with a conservative first half.
NOTE: The training and fitness was not very different because these were only 2 months apart, leaving very little time for improvements.
||The Hotter Tupelo
||The Cooler Pensacola
||September 2, 2012
||November 11, 2012
||Tupelo Race Report
||Pensacola Race Report
HR HELPS HIGHEST PERFORMANCE FOR CONDITIONS: Tupelo was just as strong of a performance given the conditions as Pensacola was. If I had gone by pace in the hotter Tupelo (without accounting for conditions) I would have hit the wall and killed my time rather than turn in a BQ-5:56. Heart rate governance helped me race as close to the edge as the conditions would allow. In Pensacola, I was also fairly close to the edge of what the conditions would allow (and they were much better conditions). So in both cases, HR allowed me to run close to my capability for the conditions.
It took a little to start HR training and racing, and it was so very worth it. I certainly recommend it for optimized training. I like to make best use of my time and this yields the most beneficial workout for the time I invest. I'm sold! I hope you are too.
- As you improve, a similar HR will produce faster and faster running. I'm now MUCH faster at 151 than I was before. This is a huge benefit of HR training... as you improve (or as you taper) your same heart rate will yield faster running.
- The testing for what BPM feels right for LT is best done within a training session because you tend to be a little more warn out in a training session. If you're tapered (not in a training cycle) the difficulty to reach that HR may not be the same as within a normal training cycle.
- You cannot do these tests when it's unusually hot because high heart rates are EASILY hit during hot weather. Perhaps surprisingly, a specific HR level is often EASIER to reach when conditions are difficult (hot, uphill, against the wind, etc.). When fully tapered, or unusually rested, etc., that same HR may be very difficult to reach. (Note: This is not always consistent with the race HR phenomenon, which I still don't really understand.)
- The terrain will also affect any testing of HR... try to use flat for consistency. You can then average any gently rolling hills for training in those conditions.
- Your Resting and Max HRs may change over time... some say max does not change, others say it does. I suspect it does, but requires a big change in fitness.
- Heart rate reactions are delayed (from a few seconds to half a minute). Smaller adjustments work best.
- Heart rate slowly increases over a run (with the same pace/conditions). It's normal.
- Start just below your target HR for a particular run, and end a little above it.
Some Great HR tips from Pfitzinger
A great place to see more basics of HR training/running... another perspective is always great to have, so I recommend learning from this page too... and others.
Great article to understand hill running
ALSO: SEE TYPES OF RUNS BELOW
||Beats Per Minute (heart rate)
||Heart Rate Training in which your effort is governed by heart rate rather than pace. Thus, one may go slower up hills, in heat, in into the wind... and faster down hills, etc.
||Heart Rate Reserve - This is the max HR minus the resting HR
||Maximum Heart Rate - May be the toughest part of heart rate training.
||Miles per Minute (internationally, it would be Meters/Min).. one of the most common methods of measuring speed (or pace).
||An athlete's speed, in the U.S. it's often measured in Miles per Minute. The rest of the world uses Meters per Minute. (Maybe someday we'll catch up.)
||Heart rate at rest - should be measured when really resting, not after getting up.
Types of training runs (following the Pete Pfitzinger & Scott Douglas' book Advanced Marathoning, 2nd edition, 2009). Each run has an outlined percent of HRR range (or percent of MaxHR range).
||Description (following Advanced Marathoning)
||A shorter, slower run meant to circulate the blood and facilitate recovery
||General Aerobic runs are usually up to 10 miles. Usually slower than LR pace and often a little faster than recovery. This allows you to put in more miles without much need for recovery.
|LT or Tempo
||Lactate Threshold runs are tough. Some describe these as "the fastest you can run for a full hour." They are high effort and are often uncomfortable. (But I must say, they can feel very rewarding once finished!)
||Medium Long Run - 11-16 miles - Same effort as LR
||Long Run - 17 and up - These are not fast. I like to run them somewhat progressively. They are meant to give you high endurance, yet not wear you out too much so you can fit in more training.
There are other types, but the intervals are short blasts so HR is not too useful there (except I sometimes refer to the ending HR).
Specific Calculations for HR Within Each Range
You can manually determine how deep into the HRR ranges you should go by using LT (see more above on this). The ranges below are examples that are close to my numbers but not exact. If you or anyone wants a spreadsheet that I created to do all the below math, just let me know. It has Pfitz percent numbers in it. You can enter your own MaxHR and RestingHR and it will create the target ranges and allow you to pick a "Current LT target HR" and then will show you that percent into each of the other ranges. Here's the math in case it's helpful.
FINDING PERCENT INTO LT: LT at 168 seems like a good goal HR (based on running that a couple times so far... I'll adjust as I learn or as I improve) and my LT range is 163-180 (according to Pfitz HRR of 77%-88%), so how far into my Pfitz LT HRR range is 168??
168-163 = 5 (so it's 5 BPM into my Pfitz LT HRR Range.
and the size of the range is 180-163=17 (BPM)... .
So 5/17=29.4% or ~30% (6/17 would be 35% so I stay conservative with 5)
FINDING A MATCHING LR HR: My LR range is (144-164). The quick math to find 30% into that range is: (<TargetHR>-144)/(164-144)=0.30 (or 30%... could use 29.4% but I didn't). That's: <TargetHR>=((164-144)*0.3)+144 which is ~150. That would be my target for the LR with these numbers.
Having issues with ones heart rate belt is very common, especially in the first couple miles. I lean on my HR heavily so I've had some experiences related to this. I'll list many of the issues I've seen and give some potential solutions or guidelines:
- Be sure it's sychronized with the watch - Yeah, it likely is, but be sure.
- Need moisture - Contacts on the belt (that touch either side of your chest) need to be wet before your sweat has a chance to provide a better connection. Salty water preferred or saliva works very well. Not being wet usually causes LOW readings but CAN be involved in high readings if combined with a slightly loose belt. Tap water does not conduct electricity as well as some think... salty water does. Tap is tons better than nothing, but saliva or salt water is FAR better! Sweat works well because it's salty. You can make a small container of very salty water and just rub some on each time before you leave.
- Need to tighten the belt - a VERY common problem. Slightly too loose usually causes high readings because your body bounce causes a cycle of contact/no-contact which can be read as a heart beat. Extremely loose can show no readings at all, but that's less common because most people would detect that and tighten it. I've only had it happen in experiments.
- Bad battery - This usually shows up as low readings. If you try a volt tester on the battery, be sure to compare to a new one. New batteries might read 3.20 volts where as an old one might read 3.03 or so... they do not appear drastically different, but in my experience, the difference can be measured.
- Contacts in battery casing - The contacts in one belt appear to have not functioned as well after a few years. I carefully bent them so they stuck out a little more, so the battery had better contact. This appeared to solve the issue in one of my belts.
- Belt chaffing - This can be for many reasons. While tightening has sometimes relieved it, I find that abbrasiveness can be from places that appear to be smooth. My solution has been to use packing tape over the areas that are causing chaffing. My synthetic Garmin belts were too easily "damaged" by simply removing the battery cover. The screw driver or coins I used to turn the lid caused some deformation of the synthetic material which chaffed very badly. I even tried sanding it until it felt smooth... still chaffing. Only the packing tape solved the issue.
- Bad belt - two of my three garmin belts have gone bad (one went bad after a few years... another purchased at the same time is still good... a third purchased just months before this writing - soft belt - was bad out of the box... I've been busy and didn't tell Garmin right away, and now they will not swap it. UGH!!! I was hoping for better customer support... I'm a Garmin fan, and have been happy in the past. Hopefully, this is an isolated incident.
- Dirty contacts - Clean off the crud buildup... use a toothbrush on the contacts. In some cases, this works like magic... in my experiences, the crud is visible. Whether or not this could be a less visible film, I'm not sure. I've had crud build up in the grooves (of the older belts).
- Belt may be upside down - I have tried this just to see what happens. In my experience the heart rate typically shows too low on the monitor. I'm guessing that all belts are made such that the brand name should be right side up.
- For a few, Belt is NEEDS to be upside down (thanks Couch2Boston)- For some people, I hear that the belts work better upside down (I'm guessing this is rare). This is likely because of specific aspects of their body and how the belt senses the heart rate. But it can't hurt to try it if you've tried all else.
- Static electricity - I've not experienced trouble from static electricity but some have reported this causing a problem before they started to sweat. (This can be made worse by technical fabric). Wetting may solve it.
- If other units are available, try swaping HR belts and/or the watch - be sure to sync' the new pair. This will help you eliminate one of them as a problem.
No reading at all usually indicates that the contacts are not sufficiently salty/wet (assuming it's actually synchronized with the watch). You can sometimes test the belt by pressing over the contact area while wearing it... if this helps, then wetting, tightening, cleaning may solve the problem. This will not likely help if the battery is bad, or it's upside down.
I may refer to my own numbers, so I'll provide the context here.
Max HR = 198 - measured 2 years ago
Resting HR = 44
HRR = 154 ....which is (198-44)
- Garmin Forerunner 305 with HR belt
- Spreadsheet to calculate %HRR numbers (download from this link)