Psychological ‘resilience’ refers to the differences between people in how they respond to and cope with difficult or stressful experiences. People who are highly resilient would be less affected, recover more quickly, and/or might actually find such events to be growth experiences. For people low in resilience, the opposite would be true.

Now here’s something to think about: many popular books and articles have mentioned the increases in mental disorder such as stress and depression over the last century, at least in the modern world. And if you think about it, there does seem to be a trend in which, as time has gone by, we’ve increased our use of technology to the effect that we physically move around much less.

Could it be that there is a causal relationship here, that our lack of movement has reduced our psychological resilience to stress? And by becoming more active, could we increase our resilience?

Stress

In a sense, everything that we do involves stress. Even just reading this sentence is placing a particular demand on your brain, so what is important here is how we respond a particular stressor. Stress is also important for growth – our bodies are adaptive and generally respond to stress by becoming more able to deal with it; provided that stress is not too high. For example, doing bicep curls with 100kg would probably be too much stress and lead to injury, but 10kg might be enough stress to increase strength.

So you could argue that placing the body under moderate amounts of stress could, over time, lead to lowered stress responses to future events, but the important point is whether resilience to the stress of exercise carries over to stress caused by other events (eg, in the workplace, traffic jams, etc).

Exercise

Two great ways to get some exercise: Walk the invisible dog, and handshake the invisible man. (Credit: mikebaird)

In one study, researchers put one group of participants on a 10-week walking and jogging program, and left another to continue their normal sedentary lifestyle. At the end of the program, the exercise group scored lower on state and trait anxiety, as well as less tension and fatigue. These factors could contribute to lowered stress responses to future events, however this was not tested directly, and additionally only 16 participants per group took part, and you’d typically want a minimum of 30, preferably more, to get a solid finding. (1)

In another study, the effects of aerobic, weight, and no training on responses to a fiendishly stressful situation were compared. Participants had to answer mental arithmetic puzzles, which flashed up on a screen too fast to complete, while listening to distracting conversations involving numbers.

Those who had undergone the aerobic training had reduced heart-rate and systolic blood-pressure responses relative to the control group (the weight training group only had improvements in systolic blood-pressure). So it seems apparent that exercise builds physical and psychological resilience to other events. (2)

Mechanisms

The mechanism of this effect is not yet fully understood, but Spalding et al (2) suggest it may by primarily due to improvements in general cardiac performance – the cardiovascular system becomes more efficient and doesn’t need to do as much work to mobilise resources in reaction to a stressor. In this way, exercise effectively raises the body’s natural ‘trigger point’ for the stress response.

Additionally, exercise triggers the release of atrial natriuretic peptide (ANP), which has a direct effect on the body’s stress response by reducing the activation of the HPA axis. This is a route through which exercise can reduce immediate levels of stress, but there may be longer-term effects too; exercise may benefit chronic levels of stress by relaxing the resting tension level of the muscles, which can reduce chronic stress by breaking the stress-feedback loop (3).

The body was ‘designed’ with the presumption that it would experience a certain amount of movement, and when this movement doesn’t take place, the body doesn’t perform up to spec. This is one example of many where we see that as humans are taken further from their ‘natural environment’, so to speak, various problems start to arise.

Recommended Reading:

• Spark: The Revolutionary New Science of Exercise and the Brain

References:

(1) Blumenthal, J.A., Williams., R.S., Needels, T.L., & Wallace, A.G. (1982). Psychological changes accompany aerobic exercise in healthy middle-aged adults. Psychosomatic Medicine, 44(6), 529-536.

(2) Spalding, T.W., Lyon, L.A., Steel, D.H., & Hatfield, B.D. (2004). Aerobic exercise training and cardiovascular reactivity to psychological stress in sedentary young normotensive men and women. Psychophysiology, 41, 552-562.

(3) Ratey, J., & Hagerman, E. (2008). Spark. London: Quercus.