Matters of the Heart – Morning Resting Heart Rate (RHR)

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Doing my ECG Stress Test

I wrote in an earlier post about Maximum Heart Rate (MHR) which is the absolute maximum beats per minute that your heart can go.

Today I wanted to share what I found out about the other end of MHR which is the RHR.

Logically, we use less energy when we at rest than when we are moving or exercising which therefore means that our dear heart should have to work less. The Morning Resting Heart Rate (RHR) is a great indicator of person’s general level of fitness (not the only one though).

To determined your RHR, take a pulse reading as soon as you wake up in the morning but make sure you don’t move a lot as movement would send your heart rate up. I sometimes sleep with my heart rate monitor so that I can measure my heart rate easily without much physical exertion. Take a watch and count your beats for 15 seconds and multiply by 4 and the results is your RHR. Do this consistently for a few days and you’ll get a pretty good trend of your RHR.

It is normal to find some well trained endurance athletes to have a RHR as low as 30 beats per minute. Cyclist Miguel Indurain was recorded to have a RHR of 28 bpm. Lance Armstrong recorded a RHR of 32 bpm.

I recorded a RHR of 60 bpm quite consistently over 4 months ago. Now it’s gone down to 50 bpm (Yayyy) which I’m quite chuffed with. I suspect it’ll go down more over the next 3 months or so.

Why is RHR important?

It is a good way to determine if you are over training. Rest is important as it allows the body to recover. If you don’t get adequate rest (and the best way to rest is to sleep), your body cannot recover sufficiently especially if you’ve been workouts have been intense and hard.  When the body suffers from over training, the MHR would increase.

If you notice your MHR increasing to more than 4 to 5 bpm then it’s time to take a rest. Don’t train. If you must train (like me who gets nervous when I don’t exercise) then go for light or even super light workouts. My idea of light workouts is to jump on my elliptical trainer for 3 minutes. Low intensity at about 65% MHR. Check your RHR the next day and if it’s still higher than normal then stop working out. If you push it, then you may end up suffering from overtraining syndrome which has a lot of long term implications.

I view the overtraining syndrome as the body’s self defense mechanism. To see improvement in ones strength and fitness a person must rest. The rest period following hard training is a magical process which takes at least 36 hours to complete. By skimping on rest, complete regeneration cannot occur. If the amount of training continues to exceed the rest period, I know my performance will plateau and decline.

The symptoms of overtraining other than your RHR increasing includes both physiological and psychological:

– Persistent muscle soreness
– Elevated resting heart rate
– Increased susceptibility to infections
– Increased incidence of injuries
– Irritability
– Depression
– Loss of motivation
– Insomnia
– Decreased appetite
– Weight loss

That’s why rest days are important. I used to skip rest days as I got quite obsessed with exercising (which is normal for a newbie). But rest days are important not only to help your body recover but also to regenerate into a much stronger body.

One very strong caveat though is that your RHR could be low if you suffer from certain medical conditions like hyperthyroidism or from overdose of medication so just keep that in mind.

For me, I am very happy my own RHR has gone down to 50 bpm. It is one of the indicators that I’m getting somewhere with my workouts and exercise. How low can it go? I’m not sure.

Let’s see what happens in the next few weeks.

At some point I’m going to attempt to write about Heart Rate Reserve (HRR) which is a way of calculating proper effort and pace by using the MHR and RHR. Haven’t really understood it so it’ll have to wait awhile.