Recovery is a very vague concept. More often than not how we feel does not fully reflect what is actually happening in the body. That’s when athlete resting heart rate comes in handy.

It’s a great way to track aerobic fitness improvements over time and also tell with a high amount of certainty if the body is in optimal condition for a training session or not.

What is Rest HR?

Resting Heart Rate (Rest HR or RHR) is an indicator of how stressed our body is. It’s a heart rate measurement generally taken first thing in the morning – even before rolling out of bed. Knowing that, athletes can consider the training stress, monitor their recovery and time their training sessions for maximum performance.

To calculate heart rate, simply put two fingers on the inner side of the wrist (closer to the thumbs) or on the side of your throat (slightly below the jaw). Count how many beats your heart makes in 10 seconds and multiply that by 6.

Related: How To Measure Post Workout Recovery And Avoid Accumulated Fatigue

If a training session takes place in the evening it’s good to check the rest HR throughout the day as well. As recovery progresses, this approach will give the athlete a better view of how the body feels and if it’s ready for the next training session.

In such case, lie down and relax for 3 minutes. After that, take the measurement and compare it to the morning one.

athlete resting heart rate
Athlete resting heart rate is a great measure to see if the body is in optimal condition for a training session.

What does increased Resting Heart Rate mean?

During the times of higher stress – physical, psychological or environmental – the body has to work harder. It processes the cortisol and adrenaline hormones, repairs the damage and, in general, normalizes all processes. All of that requires the heart to pump more blood and results in an increased resting heart rate.

These recovery activities take place even hours and days after the stress response took place. Which is why monitoring the heart rate is a good way to see how recovery progresses.

By measuring rest HR every day you can figure out the ‘normal’ or average level. That can vary by 1-3 beat per minute (bpm) on any given day due to day-to-day stress, weather, sleep quality, etc. However,

Rest HR higher than ~5-7 bpm or 10% (whichever is higher) indicates that the body is not fully recovered.

Typically, if the RHR is elevated compared to the ‘normal’ level, it means the body is under stress – be it fatigue from a hard training session or just stressful week at work.

Running & Triathlon coaching

Athlete Resting Heart Rate

Average person’s RHR is somewhere between 60 and 90 bpm. Older people tend to have lower figures and women, on average, have 5-10 bpm higher figures.

Trained athletes, on the other hand, are not normal people. Especially those practicing endurance sports.

For regular people resting heart rate under 60 bpm is a condition called bradycardia. For a trained athlete, however, such heart rate is a norm, as it allows the heart to pump the blood more effectively.

Bradycardia is when the heart doesn’t pump enough oxygen-rich blood to internal organs, including the brain. For an athlete low resting HR is not a problem, unless they feell dizziness, weakness, near-fainting, etc.

An athlete can have a resting heart rate as low as 40 bpm, but may easily increase it to 180+ beats per minute during intense exercise.

Related: 3 Ways To Determine Maximum Heart Rate And Why Athletes Need It

Athletic heart syndrome

Those who often see resting heart rate under 50 bpm (or even 40) may be experiencing an athletic heart syndrome. It’s a sport adaptation – a result of years of aerobic training.

Adaptation from regular aerobic training are increase in heart size and volume, as well as development of capillary network. That leads to more blood being pumped out and transported across the body more effectively.

So, in short, the heart muscle becomes so big and efficient that it doesn’t need to beat that many times. With each beat more blood is carried, so less beats are required. As a result, resting HR also decreases.

Resting heart rate and athletic heart syndrome
Decreases in RHR over time signal improvements in the cardiovascular fitness level.

How keeping track of rest HR can optimize training?

Coming fully rested for the key sessions is important to optimize performance. That way athletes are able to tolerate more training load and improve better. Athletes should aim to completely recover on a constant basis to make sure they are supercompensating and improving fitness.

Without a proper recovery the body will not adapt to a higher training load.

Athlete resting heart rate is a great way to track recovery. Measuring it will give an idea how the recovery after a hard training session is progressing. It will also help to notice first signs of over training and work as a reference in determining how quickly after an illness to resume high intensity training.

Training load

If rest HR on a given day is higher than usual (more than 10% from ‘normal’), athletes should take a rest day or do a very easy session in Zone 1. By training through fatigue athletes will only dig a bigger hole for themselves that they need to climb out of later.

However, if the measurement gradually climbs over a period of several weeks, then it’s a signal of accumulated fatigue. The body is, most probably, running on reserves and moving into over training. This is the time to consider taking a recovery week. It will help to grow stronger and feel much better.

I usually take a week focused on Zone 1-2 efforts every month to recover after hard weeks of training.

Related: Train Smart – A Practical Guide to Exercise Heart Rate Zones

Here’s a little example. A male runner, let’s call him Mario, has an average RHR of 45. Throughout a week of hard training his RHR was around 46-49. On Saturday night he went to dinner with friends and stayed up late. Waking up the next morning his RHR jumped to 56, which shows that the body hasn’t recovered at all and requires extra time off.

If Mario will ignore this and go for a hard session, it will not be as productive and will get him even more fatigued. The best solution would be to skip the session, considering a solid training block that he needs to recover from.

Illness

Athletes are generally eager to get back into training after an illness. However, resuming intense training schedule after the first symptoms have subsided is not the best approach.

Very often even if we feel better, our body still struggles with stress.

During an illness, the body temperature increases and, as a result, RHR also increases. It’s estimated that for every 1 °C increase, RHR can jump by 10-15 bpm, because the body is working overtime to cool itself and fight disease.

As the body recovers from an illness, resting heart rate also decreases. Sometimes an athlete may feel healthy, but the RHR is still high. It’s a good indication that the body is not 100% healthy yet. In such cases it’s best to resume training only in aerobic mode (Zones 1 and 2) until RHR gets to the ‘normal’ state.

Some viruses need a couple of weeks for the body to fully combat and recover from.