Categories: Train

Heart rate monitoring | The best way to find the sweet spot of exercise intensity

August 9, 2018

If we’re lucky enough to have found our passion, the chances are we exercise out of the sheer joy of it. We do our chosen sport because it’s our thing, our way of life – and it’s fun and makes us feel awesome!

In addition to the fun and feel-good factors, most of us have specific sports and fitness goals we want to achieve; be it weight loss, gaining strength or boosting endurance. But how do we know if we’re hitting those goals or even headed to the right direction?

Why mEASURE exercise intensity

The intensity level of exercise (together with duration and frequency) determines how effective your training is. If you want your workouts to be effective (in addition to being fun), you’ll need to know if the intensity of your training session was what you planned. To make sure you on the right track, you’ll want to know if your high intensity session turns out to be a light effort thing.

To improve your fitness, it’s crucial to not only monitor if you’re doing enough but also to make sure you don’t overtrain.

To improve your fitness, it’s crucial to not only monitor if you’re doing enough but also to make sure you don’t overtrain. As counterproductive as it sounds, if your training is too intense or repetitive with no variation, it can, in fact, hamper your performance and/or put you at risk of injury. Especially if you rigidly focus on one thing and one thing only – it’s rarely enough.

You can overdo any form of exercising, even something as simple and seemingly low effort as walking – walk too much, too often, while ignoring strength training and stretching, and you may soon find yourself with lower back pain, aching hip joints, inflamed Achilles tendons or knee problems.

Specific goals or not, it’s key for all exercisers to find that sweet spot where you’re exercising enough, at the right intensity without overdoing it. But, how to find it?

Two indicators of exercise intensity

Exercise intensity is a measure of how straining a physical activity is for you – it is always personal. This means the exertion from the same exercise may be completely different to different people so what feels to you like a tough workout may feel like an easy walk in the park to someone who’s more fit.

There are two ways of determining exercise intensity: your subjective feeling and a physiological measure – your heart rate.

It’s important that you listen to your body.

The first and most simple indicator of exercise intensity is how you feel during exercise – so it’s important that you listen to your body. Although based on subjective assessment, studies show that the perceived level of intensity compares well with heart rate – if you feel that you’re working hard, your heart rate is likely high.

The most accurate way to gauge the intensity of your workouts is monitoring your heart rate.

The most accurate way to gauge the intensity of your workouts is monitoring your heart rate. It’s important to pay attention to your subjective feeling, but the most reliable and comparable measurement of exercise intensity is heart rate data. Heart rate takes into account your body status and readiness. It’s mainly physiological, but is affected by mental aspects, too.

Heart rate monitoring turns guessing into knowing

Monitoring your heart rate is key in making sure that you exercise at all the intensity levels and have enough variation in your routine. When you use a heart rate monitor, you can more reliably monitor if you stay at the intensity level you planned: you will better manage to maintain a light effort throughout your workout or reach the peaks in interval training – you will know, instead of just guessing by the way you feel.

When your fitness improves, you may notice that the same heart rate allows you to run or cycle faster or with the same speed, your heart rate is lower. These are clear signs that your fitness level and body capacity have improved.

To improve your fitness you need to vary the intensity of your workouts. This means you need to train on different heart rate zones, which target to show the full range of training possibilities.

High intensity isn’t automatically better…

High heart rate improves your aerobic fitness but it’s physiologically demanding to your body and its functions – the more you train with high intensity, the more time you need to recover. This means you can’t and shouldn’t do high intensity training every day or – depending on your fitness level – not even every other day.

For most regular exercisers, two or three times of high intensity training a week is enough. The reason you shouldn’t overdo it, even if you want to challenge yourself, is that too much training at high intensity increases the risk of injuries.

Too much training at high intensity increases the risk of injuries.

Even if you don’t end up with a physical injury, overdoing high intensity training for too long will result in a deficit in hormonal and metabolic functions and you may lose your appetite, get irritated or sleepy and have disturbed night sleep. This phenomenon is known as the overtraining syndrome that can put a full stop to your training altogether.

… but ONLY low intensity isn’t enough

On the other hand, training at low intensity only, doesn’t take you forward or improve your fitness. That’s why you need the variation.

Training at low intensity maintains the bodily functions and prevents many metabolic disorders. It consumes calories, but little compared to moderate or higher intensities.

Low intensity sessions are good for recovery and also in supportive training, like stretching, yoga or pilates to improve your mobility.

Low intensity sessions are good for recovery and also in supportive training, like stretching, yoga or pilates to improve your mobility.

So, how to balance the highs and lows?

Varying and selecting trainings with high, moderate and light is the best way to go: light intensity allows you to recover or build base, moderate to improve and high intensity to peak your fitness.

Varying and selecting trainings with high, moderate and light is the best way to go.

The amount of different intensities depends on your fitness level. If you’re highly fit and exercise frequently, you can do 2-3 high intensity training sessions a week (but not on consecutive days) and complete your program with 2 moderate and 1-2 light ones weekly.

If you work out three times a week, select one high and two moderate training sessions or one of each (high, moderate and light).

These are only general guidelines to point you to the right direction. If you want to set specific personal goals, you can create training targets with Polar Flow, sync the targets with your sports watch or fitness tracker and your Polar product will guide you during your training.

Avoid the #1 mistake in heart rate monitoring –  calculate your max heart rate

The number one mistake exercisers make with heart rate training is that they don’t find out what their personal maximum heart rate is. This leads to either underestimating or overestimating all the intensity levels and doesn’t really provide the accuracy that heart training can and should.

Before you do anything, calculate your maximum heart rate.

So, before you do anything, calculate your maximum heart rate and set it into your HR monitor to get the right submaximal values for training intensities.

The most reliable way to find out your max heart rate is a lab test but if that’s not possible, the next best method is to do a field test on your own. If all else fails, the “220 minus your age” formula can give you a ballpark estimation of your max heart rate but since heart rate is individual, using a general rule of thumb is not waterproof (like most of Polar heart rate monitors are).

When you know your max HR, you can move on to calculate your personal heart rate zones. Of course, if you use a heart rate monitor, the device will calculate the zones for you based on your max and resting heart rate. Then, you can successfully train with different intensities to build up body fitness and capacity safely and effectively.



Please note that the information provided in the Polar Blog articles cannot replace individual advice from health professionals or physicians. Please consult your physician before starting a new fitness program.