Image Of An Athletes Measuring Mental Stress Using Hrv On Trainingpeaks App

Measuring Mental Stress With HRV

BY Simon Wegerif

You may think training is your biggest stressor, but daily life may play a bigger role. Find out how to manage stress for better recovery and performance.

Unless you are a professional athlete looked after by a support team, training is rarely the largest source of stress in your life. Mental stressors like work, family and lifestyle demands may actually be the key factors in determining how well you recover and perform.

How Mental Stress Impairs Performance

A 2010 study in Australia tracked 30 well-trained club triathletes throughout an entire season of training and competition. The study monitored their perceived stresses from all lifestyle factors, as well as from training itself (which averaged 10 hours per week).

While the number of training sessions per week (and especially run sessions) affected the likelihood of injury, psychological stresses actually had a larger impact. The study found that when mental stress increased, it was possible for athletes to become overtrained, even when training remained constant. They also found that athletes’ perception of their ability to complete planned training impacted their stress levels. Notably, this included occasions when the athletes’ perceived their planned training to be too easy, and therefore unlikely to generate the desired gains in performance.

To quantify the effects on performance further, a 2012 study on 44 healthy adults in Finland looked at levels of psychological stress during a short two-week intensive training program. Subjects rated their stress from one (low psychological resources and a lot of stressors in my life) to ten (high psychological resources and no stressors in my life) during the program.

This study found that those with the highest levels of stress showed almost no increase in maximum cycling power over the two-week program compared to power increases of up to 19% for those experiencing the lowest levels of life stress. Other studies have also shown reduced running economy following stressful life events.

Sources of Mental Stress

In addition to the general lifestyle stressors experienced by the general population, endurance athletes have some added challenges, such as:

  • The required time commitment to training and consequent sacrifices made by the athlete and their family.
  • Concerns about doing sufficient training of the right kind to optimize performance gains without overtraining.
  • Remaining committed to training, particularly when training is hard work, when training alone or in bad weather.
  • Pre-event logistics and worrying that something might go wrong during the event.
  • Balancing pacing with pushing to the right extent to keep up with competitors.
  • Remaining focused when training or other aspects of life are not going as well as expected.

How Stress Adds Up

The principal of Total Load describes the way the body adds up stresses from different sources. Essentially, Total Load = Physical Stress + Chemical Stress + Mental / Emotional stress. This “total load” is what the body must react to.

Another way to think about it is that everyone has a stress budget (or ‘stress bucket’) and using it on one kind of stress means there is less budget available for other kinds of stress. Spend more than you have, and overload occurs.

Of course, you can increase your budget, or resilience, by training and recovering. Performing high volumes of low intensity training, then sleeping and eating well, for example, can teach your body how to deal with that physical stress more efficiently.

Quantifying Mental Stress

Probably the most-used objective stress measure is a salivary cortisol test. Known as the stress hormone, cortisol has beneficial effects over short periods (like helping you wake up or respond to stimuli) but can impair adaptations and health when present in too high concentrations for too long.

But what do you do if, like most of us, you can’t perform a salivary cortisol test at home? A recent study looked at the relationship between cortisol and the more-easily-measured heart rate variability (HRV) in 171 healthy adults who were given a series of demanding mental exercises, designed to produce a stress response.

What the study found was that drops in HRV in anticipation of the stressful task predicted subsequent increases in cortisol during the task itself. This makes HRV a useful proxy, and even a predictor of the body’s response to mental and emotional stress:

Managing Mental Stress to Increase Performance

Along with learning relaxation and coping techniques, you can also improve your ability to manage stress through lifestyle changes outside the workplace. Eating a healthier diet, exercising, and taking some time to do things that you enjoy have all been found to have a positive impact on stress levels and management.

Regular HRV monitoring can also help you by allowing you to see which activities work the most in your favor when it comes to de-stressing. At rest, a healthy person’s heart rate varies between beats, and research has found evidence that high HRV is linked to good health and better fitness levels—while decreased HRV is linked to fatigue, stress, and even burnout.

Here are some tactics to try and measure to see which works best for you:

  • Getting more sleep and improving sleep hygiene
  • Eating regular meals and snacks at home and work
  • Reducing your caffeine intake
  • Giving yourself more time to prepare for events and competition e.g. by making packing lists, timetables and travel plans
  • Developing contingency plans for training and events: ‘if… this happens, then I will do…that’
  • Taking a walk outside on your lunch break
  • Getting more sunlight at work by sitting near a window or stepping outdoors for a few minutes
  • Spending time with friends, family, and pets
  • Meditation
  • Yoga or Tai Chi


Main, L.C. et al. (2010, December). Training patterns and negative health outcomes in triathlon: longitudinal observations across a full competitive season. Retrieved from

McCormick, A. et al. (2016, November 17). Psychological demands experienced by recreational endurance athletes. Retrieved from

Pulopulos, M.M. et al. (2018, May 3). Association between changes in heart rate variability during the anticipation of a stressful situation and the stress-induced cortisol response. Retrieved from

Ruuska, P.S. et al. (2012, March 12). Self-rated mental stress and exercise training response in healthy subjects. Retrieved from

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About Simon Wegerif

Simon Wegerif is a serial entrepreneur, inventor, and biomedical engineer. He was previously an executive with Philips Electronics in the UK and Silicon Valley. Simon is a competitive cyclist and has also completed a number of triathlons including Ironman distance. He created ithlete, the leading, scientifically founded HRV app in 2009 after identifying an opportunity for using HRV in his own training. He is considered an expert on the topic, having read over 1000 papers and frequently consults with industry experts.

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