Exercise: It’s What’s Inside That Counts

Exercise elicits the release of Beta Endorphins, which are 5-10 times more powerful than morphine. Exercise can be an effective tool for dealing with depression. Exercise enhances grey matter (i.e. brain) growth. Here are a few reasons why I like exercise, beyond what happens to the outside….

Recently, I wrote a blog post to discuss the ways women are portrayed in the media. My goal was to highlight this somewhat depressing issue: women are often pressured to adopt unrealistic standards for their body in the guise of being ‘fit’. An interesting question came up in the comments: someone asked me how I would motivate people to embrace fitness, if not by invoking sexiness.

Make no mistake, improving your health and getting comfortable in your own skin will have some crossover benefits in the ‘sexy’ department. However, vanity ranks low on my Exercise Totem Pole, and I thought I’d take a moment to describe why.

In order for an exercise habit to stick, it needs to be personally gratifying. It has to have more relevance to your life than a pant size. When I learned to use exercise as a psychological tool, I saw huge physical improvements too.

I’m not going to waste your time with words like ‘zen,’ fist pumps, or other ideology to make the point that exercise is awesome. I am going to tell you about my own issues, and some new (and old) biological references that demonstrate the physiological, psychological, and maybe even psychiatric benefits of hitting the gym on the regular.

The transition from using external motivational cues (like clothing size and a perceived view of sexiness) to internal, rational motivation helped improve my entire outlook on health and wellness.

The Initial Fitness Mission: Bringing Sexy Back

Can we be real? The initial prod toward the gym often comes from how you feel about your exterior. Yes, improving blood lipid profiles sounds like a nice side effect, but a little irrelevant, if I’m being honest about my reasons for exercising. When my twenties hit, something happened.

Oh, wait. This happens to everyone: metabolic slow down.

I had three options for dealing: be content with my new shape, eat less, or exercise more. Guess what? I wasn’t getting happier or more zen-like regarding my body. I started to exercise.

I spent years ‘exercising’. That word is in quotes because while I went to the gym, and was fit and happy, I didn’t understand how to use exercise as a psychological tool until I faced Real Stress. As in, Doctoral Research stress.

Fitness Mission Two: The Anxiety Busting Effect. The Brain, Stress, and Reward Circuitry

Truth be told, doing a PhD was pretty intimidating. Today I am a psychologist with a background in eating behavior. This should make my ‘dietary adherence’ so much better than yours, right? Well, not exactly.

Midway through my PhD, I started running with one of my lab mates. I noticed that when I ran, I stress-ate a lot less. I also noticed my mood improved. I mean, this was apparent when I was still logging hours on the Stairmaster, but I only really started to…um… feel the buzz when I actually started running. Sorry! I’m trying to avoid cheesy fitnessisms, not embrace them. ANYWAY.

One caveat: my stress eating wasn’t a huge problem, but it was surprising and a little amusing to realize I had eaten half a box of cereal while analyzing data. It stopped being funny when my pants didn’t fit.

Hellish as the 5:30 wake up drill was, I started doing 5 km runs before getting to the lab. Unconsciously, my cereal intake went down. I upped my morning ritual to 10 km, three days a week. The benefits manifested themselves in the ways I handled the terrifying possibility of failing/overextending the time it took to finish my academic research, a project I truly enjoyed.

I ran through the write-up of my PhD, which took about a year. I maintained a healthy body weight during that time. Not stick-thin and not embarrassed by puffy cheeks, either.

I’ll say it: the worst part of weight gain for me is the puffy cheeks!

Integrating a demanding commitment to physical activity helped me do more, not less. I’m not sure where I would have wound up had I put on another 20 pounds while working on my PhD. I think I would have been pretty irritated with myself.

When stress levels creep up to your eyeballs, how you look in a bikini is not your first priority. However, both aerobic and anaerobic exercise can help minimize the panicky feeling that results from overflowing stress levels. If looking great is your only reason for going to the gym, it’s no surprise that your membership card is going to gather some dust. Instead of the way your body looks, focus on how your brain feels.

I’ve written up a brief guide to explain the psychological, psychiatric, and stress reducing benefits of hitting the gym.

When I refer to my own stress eating, I find a bit of comfort in knowing I’m not alone. 42% of all students report an increase in eating during times of stress, and 73% report more frequent snacking. I’d wager the actual numbers are even higher, since the last study was self-reporting.

What is Stress, Specifically?

Stress is what happens in the face of any extremely challenging, uncontrollable or overwhelming event. The event can be emotional or physiological. The real question is, are you able to regain stability afterward?

Certain behaviors are better at achieving homeostasis (science speak for stability) than others. Exercise can be used as a coping skill, just like binge eating can, but why would we do either? Why can’t we just roll with the punches life sometimes doles out?

Stress events can include interpersonal stress, job loss, physical injury, loss of a parent, or even the daily grind, especially if you goes for too long without a break. Get used to the fact that life changes, sometimes not for the better. In response to the terrible coincidences that life doles out, we often need to do something to overcompensate. Due to the immediate relief associated with ingestion of food, cigarettes, alcohol, these become quick solutions (just meditating on stress is a technique that takes years of mastery. Here, I’ll use the word: it takes a lot of being very Zen, a quality I lack). Thus, an important question for scientists is to focus on behaviours that actually reduce stress long term. Immediate pleasures actually lead to more stress, but here is some fascinating insight into the biology of stress, reward, and why we often go for immediate pleasure in the face of immediate stress.

Where is Stress, Specifically?

Stress circuitry has a big overlap with areas in the brain that control appetite and energy regulation. The hypothalamus is generally regarded as the body’s thermometer, regulating energy balance and telling us when we need to eat. The hypothalamus also plays a critical role in stress circuitry: when we experience stress, we experience increased activity in the Hypothalamic Pituitary Adrenal (HPA) axis in the brain.

Certain activities can have an immediate effect on the HPA. Eating highly palatable food, for example, reduces the activity at the HPA junction almost immediately, particularly if the food is high in sugar and fat. Most rewarding behaviors like sex, drugs and alcohol, can also efficiently dim the noise stress produces in your brain. You may not have control over life events, but you can control how you deal with them.

Eating in response to stress becomes a learned behavior, and an easy coping mechanism in the context of our dynamic and ever-changing environment. Today’s world positively teems with high fat and high sugar food. It’s not hard to see how stress eating happens. I’m more skeptical of a person who doesn’t stress eat, than the person who has either learned coping mechanisms or admits to having difficulty with pumpkin pie during key moments in their life.

I was starting to rely on terrible cereal as a way to face my mounting data sheets. Thanks to the ‘kick in the head’ that morning runs bring, I effectively manage this learned habit. I don’t keep cereal in the house anymore (SAD EMOJI), but I can fit into my pants (HAPPY FACE).

Stomach Issues, PMS, and Another Reason for Exercise

If you’re one for chronic stomach knots (IBS – I won’t go into details), nothing helps like a decent run. Many early runners find running can actually cause stomach cramping as a result of blood being directed away from the stomach to where it needs to be most. Since your muscles, heart and body are needier during a 10 km jaunt, the decrease in blood available to the GI system can decrease your body’s ability to absorb fluids, which leads to cramping.

However, I have discovered over the years that running significantly alleviates stomach cramps. I couldn’t find any easily accessible PubMed articles for evidence, but one body of research I’d like to draw from includes the finding that aerobic exercise significantly reduces PMS pains.

Researchers investigated whether using exercise as an intervention was helpful in improving PMS symptoms, testing three groups of participants: High Intensity (50 minutes, 3 times a week, at 80-85% max heart rate), Moderate (60-65% max heart rate), and a control group that did not exercise.

While the improved mood effect is a nice feature of this study, the biological rationale is pretty awesome! One key point is that endorphins increase during aerobic exercise, a key player being beta-endorphin. Beta-endorphin can be 5 to 10 times more effective in pain reduction than morphine! Beta-endorphins have a regulatory effect on the hypothalamus (that again), and regular aerobic exercises will maximize your beta-endorphin levels during the later part of ‘That Time of the Month.’

The universal puffiness we experience can also be alleviated by exercise. Puffy symptoms of PMS relate to increased blood serum levels of a few hormones and vitamins. Specifically, aldosterone, prostaglandin, vitamin E2 and B6. Period pains relate to increased blood serum aldosterone, rennin-angiotensin and decreased levels of progesterone and estrogen.  Regular exercise helps sort these out: it decreases rennin while increasing estrogen and progesterone levels. For more detail, please see:

Exercise Stimulates Your Brain

There are too many articles about the effects of exercise to cover in a blog post. A book might be capable of covering the neurocognitive, psychological, and psychiatric benefits of exercise, but I’ll list a few nifty ones here:

Biggest Winner? Exercise Enhances Neuroplasticity

Neuroplasticity is the term used to describe the nervous system’s capacity to modify its organization to changing demands. Wait a minute … stress is related to ‘changing demands’. The better you cope with change, the less likely you’ll be to reach for Oreos instead of your running shoes.

Neuroplasticity has been studied on a variety of levels, but personally I find the psychological arena most interesting. If it’s a consequence of adaptive behavior (like learning a new language, or engaging in physical exercise) neuroplasticity enables effective, adaptive behavior, increased executive function, grey matter growth (i.e. brain growth), production of Brain Derived Neurotrophic Factor, a longer attention span, and a faster speed of processing. With time, research funding, and curiosity, the list will likely grow.

I’ll cut to the chase. Here is some evidence for the cognitive benefits of exercise:

  1. In adults, there is evidence to show exercise is linked with dementia prevention. One study examined a cohort of 1919 middle-aged participants at three points in time, spanning a time period of 17 years. Physical exercise at the age of 36 years was associated with a slower rate of memory decline between 43 and 53 years of age. Participants who stopped exercising after the age of 36 showed a lower protection of memory function than those who started at 36, suggesting exercise has to be continuous in order to be effective.
  2. Other studies have shown a reduced risk of dementia at older ages (50 years old) when participants have been engaged in physical exercise. Midlife physical activity might contribute to brain health in later life.
  3. Physical activity has been recommended as a way to prevent further memory loss in patients with dementia.

Exercise increases Brain Derived Neurotrophic Factor (BDNF). BDNF? It’s really important!

Neurotropic factors (NFs) are responsible for growth, differentiation, and the survival of neurons. BDNF is the most prevalent growth factor in the central nervous system, and physical exercise increases BDNF not only in the brain, but also in the blood. Low BDNF levels are found in patients with neurodegenerative diseases, such as depression, post-traumatic stress disorder, schizophrenia, obsessive compulsive disorder, addiction, and ADHD.

Pharmacological intervention, like anti-depressants and anti-psychotics, have been found to increase BDNF levels, but the finding that you can generate BDNF through exercise is fairly significant.

Currently, researchers are trying to isolate which types of exercise lead to the greatest and most effective production of BDNF. I wish I could be more explicit, but the vague answer is this: aerobic activity with resistance training improves spatial memory and mood, but via distinct mechanisms. Aerobic activity modulates hippocampal BDNF, while resistance training works through other means (central Insulin Growth Factor, which plays a key role in spatial recognition).

Though stress reduction is one of the most immediate benefits of physical exercise, brain insurance is another.

Exercise and Insulin: The Final Chapter

The final point I’ll make is for anyone concerned about blood sugar. My expertise is in eating behavior, so this is another excellent feature of exercise. It has beneficial effects on insulin sensitivity for both healthy and diabetic populations.

A single dose of exercise has shown to have a beneficial effect on insulin sensitivity for at least 16 hours after exercise. In studies looking at a walking intervention, researchers found 170 minutes of exercise per week improved sensitivity significantly, compared to only 115 minutes per week. Interestingly, intensity had no impact on insulin response.

External cues and motivations may help you find the time to hit the gym when you first start, but when stress and life begin to pile on, you’ll find that an internal drive and motivation will far outweigh your interest in looking beach-ready. Brain insurance and health come first, and if you take care of yourself properly, the beach-bod may come too.

… But regarding the latter? Who cares?! When you’re protecting yourself against dementia, period pains, and neurocognitive decline the bathing suit doesn’t seem all that important anymore.


  1. Richards, M., Hardy, R., Wadsworth, M.E., 2003. Does active leisure protect cognition? Evidence from a national birth cohort. Soc. Sci. Med. 56, 785–792.

  2. Andel, R., Crowe, M., Pedersen, N.L., Fratiglioni, L., Johansson, B., Gatz, M., 2008.Physical exercise at midlife and risk of dementia three decades later: a population-based study of Swedish twins. J. Gerontol. A Biol. Sci. Med. Sci. 63, 62–66.

  3. Rovio, S., Spulber, G., Nieminen, L.J., Niskanen, E., Winblad, B., Tuomilehto, J., Nissinen, A., Soininen, H., Kivipelto, M., 2010. The effect of midlife physi- cal activity on structural brain changes in the elderly. Neurobiol. Aging 31, 1927–1936.

  4. Intlekofer, K.A., Cotman, C.W., 2012. Exercise counteracts declining hippocampal function in aging and Alzheimer’s disease. Neurobiol. Dis. (Epub ahead of print).