Hello All,
I've recently managed to run a steady 5k on the treadmill two or three times quite happily but I'm concerned about my Heart Rate. My Max Heart Rate is (220-70) 150. I always warm up for five minutes and cool down for the same amount and when I finish my 36min run I feel great and not exhausted. But my HRM shows my HR to be 155-160 for about 25 min of the run. Should I be worried about this?
In the global running community, the formula for max HR that is commonly used by the medical fraternity has been well and truly discredited. Max HR is unique to each individual and differs between men and women (of the same ages) . I am 72 and I have recorded a max HR of 167 a number of times - all after a hard finish in 5K foot races. This is almost 20 higher than the medicos say. 
True max HR for older people is further away from the formula than it is for younger people - because the decrease with age is not linear ( as the formula says it is) . It is very difficult for most people to get anywhere near their max - and if they ever do so it will only be for a very few minutes ( probably also throwing up in the effort) !! An "educated guess: re your 25 minute values of 155-160 would be this would represent approx 80% of your true max HR - a lot depends on how aerobically fit you are - can also depend on the accuracy of the measuring equipment
As Bazza1234 has said, there re so many ifs and buts that its hard to be definitive. You don't say if you have any cardiac issues, whether you are on any meds or whether this 'high' rate is a new phenomena. If you've been doing 5k runs for a while and this 'high' rate is a new thing then it might be worth a visit to your GP for reassurance if nothing else. If you have had a cardiac event, then again, you should probably have a chat with your GP since this would be regarded as being a high heart rate. Best advice I ever got was listen to your body - if it feels OK then you are probably OK.
Hi Steve and Bazza, thanks for your replies. I did my first Parkrun today in 33 mins and feel great while HR was up in the 155-160 for most of the run. So "listening to your body" seems to be the best advice for me. Thanks.
You haven't said what device you are using to measure HR while running
I am 69, had bypass 5 years ago but feel in great shape as I exercise regularly and eat good nutritionly. I started Parkrun recently and done 7 so far but nw given up as winter is coming and cold is not good for people with heart disease. However, I was shocked to see my Fitbit HR monitor showing peaks of 160 and 170 for the sections when I was jogging. My PB is just under 34 mins but I can’t keep jogging without have short walking breaks. I feel comfortable but don’t want to push my luck so will keep monitoring and attempt to keep my HR to max 150 when/if I start Parkrun again. It had been good fun and I did enjoy it, so looking forward to next Spring and perhaps starting again.
For a normal fit person max heart rate is calculated 220 minus your age. Is this what your 70 figure is? Using the 150 figure you should only be training to 80% of that 150 figure, so really you should be working to 'around' the 120bpm mark
These are very general calculations but do not take account of how everybody is different.
Only you know how you feel, before, during and after training, but even a fit 20 year old shouldn't be hitting the bmp figures you give.
Are you using a quality heart rate monitor with a chest strap? Or a 'fitbit, which I can only describe as being good for telling the telling the time and very little else.
You do not mention if you have any cardiac conditions or any medications which also come into play
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