How Stress Makes it Harder to Get Fit and Healthy

How Stress Makes it Harder to Get Fit and Healthy

Have you ever struggled to stay consistent with regular exercise and healthy eating behaviors?

You’re not alone.

Despite having the best intentions, many of us end up derailed by life’s constant demands and the mental stress they add to our lives and end up feeling unable to keep our physical and mental well being in check.

If that sounds like you, first let’s just collectively take a moment to acknowledge that behavior change is HARD. Human brains are programmed to wire for efficiency and repetition. So when we try to overhaul our unhealthy eating habits and start exercising regularly, our brains have to work harder and devote more mental energy to getting through the day.

Unfortunately, for that initial period where we’re starting out with new habits, it just plain sucks. But through repetition, our brains can rewire for efficiency with the new exercise and eating habits — we just need to hang in there long enough for that to happen.

But, in my experience both as coach and as a busy woman trying to juggle owning and operating a small business, my family responsibilities, and my other commitments while also lifting weights, making healthy meals, and training for ultramarathons, there is one thing that tends to make the whole process even harder … stress.

Regular, chronic stress is strongly correlated with many of the behaviors and choices that sabotage our efforts to break unhealthy behaviors and as a result can cause poor physical and mental health and lead to weight gain.

Let’s explore how stress makes it harder to live a healthy lifestyle.

Stress increases cortisol

Periods of chronic stress can lead to an increase in stress hormones or elevated cortisol levels. A 2018 study, showed that cortisol secretion levels in stressed periods were found to increase about 9 times compared with relaxed periods. In other words, stressed women can have 9 times the cortisol as non stressed women.

Cortisol is a hormone that’s released in response to psychological stress due to a real or perceived threat. Cortisol initiates fight or flight mode and essentially makes more energy available to you for immediate use so you can fight the threat or run from it. Cortisol does this by increasing the amount of glucose in your blood and countering the effects of insulin to keep your blood sugar levels up until the threat passes. This stress hormone system makes sure your body is ready to meet the demands of the stress it’s subjected to.

Cortisol gets a really bad rap in modern society but it’s not a “bad” hormone – it serves an important purpose like all hormones. We need healthy, responsive cortisol levels to help us cope with stressful events and situations.

However, cortisol was meant to be released in short bursts like when you see a bear in the woods. It wasn’t meant to be something we slow drip into our systems all day every day. So the problem is that modern lifestyles which involve long periods of stress or perceived stress can create prolonged exposure to higher cortisol which can have long-term effects on the entire system — including difficulty sleeping and reduced insulin sensitivity a hallmark of prediabetes.

Remember that when cortisol increases, it disrupts your ability to relax, energy availability, and blood sugar levels – good when you need to run for your life, not so good when it stays in your system.

Stress hormone (cortisol) levels makes it harder for you to get enough sleep and good sleep quality

Persistently-high levels of stress can lead to persistently-high cortisol levels which disrupts the rhythm and balance of other hormones and interferes with your ability to sleep – a double whammy.

Studies show that disturbed sleep cycles and sleeping 5 hours or less per night are associated with a 2-4 times increase in your risk for developing obesity compared to sleeping 7-8 hours per night (Patel et al., 2008).

The exact reasons why this is are still being studied but it appears that it results from a combination of factors such as:

  • a reduction in your metabolism (specifically your resting metabolic rate) to compensate for lack of sleep;
  • hormonal changes to appetite and hunger brought on by low energy from lack of sleep;
  • a change to brain stimulation which may trigger the selection of foods that have a lot of calories and take less energy to digest (like uncontrollable cravings for brownies and french fries because of their high-energy/calorie content) which makes it harder to stick to healthy eating habits, increase the calories you’re eating, and reduces the part of your metabolism that powers food digestion; and
  • a reduction in daily activity, fewer steps taken, and less physical exercise because when you’re tired from not sleeping, you don’t really feel like moving or exercising.

Let’s break these down individually to get a better understanding of the mechanisms that drive stress-related weight gain and why stress reduction is so important for our physical and mental health.

Reduced Sleep Decreases Your Metabolism

Several studies have found that otherwise healthy adults experience a small reduction – around 3% – in resting metabolic rate (RMR) after as few as five days of reduced sleep (Spaeth, Dinges & Goel, 2015).

While that may seem small and insignificant, RMR makes up the majority of your body’s daily caloric expenditure. Over time, that small daily percentage can add up and if you’re not reducing how much you eat at the same time, you’ll be in a calorie surplus which can lead to stress related weight gain – especially when combined with the other factors below.

Additionally, another way stress can reduce your metabolism is by lowering the thermic effect of feeding (TEF) which is the part of your metabolism that make up the calories it takes just to digest your food.

TEF is the part of our metabolism that is dedicated to powering digestion – it’s the energy it takes to digest our food. Each macronutrient (carbs, fat, protein) has a specific metabolic “cost”.

Protein has the highest thermic effect and carbs and fats have a lower thermic effect, meaning that they require less energy to eat and digest. When we’re tired and stressed, we typically choose lower thermic effect, high-carb and high-fat options (like donuts and sugary foods) over the higher thermic effect protein options (like a chicken breast of omelet) – thereby reducing our metabolism.

Reduced Sleep Alters Appetite and Hunger Hormones

Have you stayed up later than usual and found yourself feeling extra hungry the next day? Sleep loss is associated with a decrease in leptin and an increase of ghrelin in your blood.

Leptin is a hormone that tells your system that you’ve eaten enough food to meet your calorie needs for now and your energy stores are topped off. Leptin decreases your appetite when you’ve reached the point of meeting your body’s energy needs. When levels of leptin in your blood are low, your appetite increases and your energy expenditure decreases to conserve energy.

Ghrelin is often called the “hunger hormone” because its release stimulates your appetite and promotes increased food intake and energy storage. This is your “low fuel” light. When it goes off, your body is telling you it’s time to fill up the tank. It also prepares your body to store away the extra calories for later. Ghrelin has essentially the opposite effect as leptin.

With sleep restriction, leptin goes down and ghrelin goes up, so your hormones are driving you toward eating more. And so less sleep often means more grabbing for extra food and that can lead to weight gain.

A 2015 study found that two consecutive nights of sleep restriction (4 hours of time in bed) was associated with a 28% increase in ghrelin and 18% reduction in leptin during the day, leading to increased hunger and appetite, mostly for energy-rich foods with high carbohydrate content and low nutritional quality, such as sweets, salty snacks and starchy foods.

So not only are these two hormones – leptin and ghrelin – regulate your appetite and level of satisfaction and signal you to tell you it’s time to eat and time to stop eating.

But they are also telling your metabolism to speed up or slow down and regulating fat storage.

Reduced Sleep Alters Food Selection

The evidence suggests that when we lose sleep, we’re more susceptible to making poor food choices, largely driven by the hormonal changes above. Stress makes it less likely that you’ll choose a diet rich in nutrients.

Lack of sleep is also associated with a “stimulation of brain regions sensitive to food stimuli” which indicates that reduced sleep could lead to the selection of high-calorie foods (Delhanty and van der Lely, 2014). So it’s not just that people who sleep less tend to eat more calories, it’s also that the foods selected tend to be high-fat and sugar-dense foods (Shechter et al., 2014).

A study in the European Journal of Clinical Nutrition found that people who do not get 7 or more hours of sleep per night consumed an average of 385 extra calories the following day (Khatib, Harding, Darzi, & Pot, 2017). Do the math: it takes about 3500 extra calories (above your TDEE) to gain a pound of fat mass so it adds up. So, as you can imagine, good sleep hygiene is critical for optimal health but also for minimizing weight gain in midlife and beyond.

Sleep deprivation as a result or one or more stressors also can alter your food cravings and make it very difficult to engage in the mindful eating behaviors that help you maintain a healthy weight. And the stress of our packed lives and packed schedules may cause us to eat more convenience or grab-and-go food options which are typically much higher in calories than the meals we might cook for ourselves. Eating while in a rush or multi-tasking can also cause us to be less aware of what and how much we’re eating — another way stress can sabotage our plans to eat healthier.

Stress also inhibits your ability to choose healthier comfort foods. Using food to cope with negative mood or emotions (emotional eating patterns) when you’re feeling stressed, also usually involve fatty foods and sugar cravings.

Reduced Sleep Makes Us Move Less

A 2015 study found that individuals who sleep less are more likely to experience fatigue and sleepiness during the day, which may discourage them from daytime physical activity and promote sedentary behaviors. This combination can cause weight gain, high blood pressure, immune system suppression, and poor mental health.

Without adequate sleep, you won’t feel like moving around as much during your day which lowers the amount of calories you burn from non-exercise activity.

The non-exercise activity thermogenesis or NEAT is the amount of energy it takes to move around as part of your daily life (not including your intentional exercise or structured physical activities). For many of us, this might include walking from your desk to the bathroom, making your bed, fidgeting in your chair, doing household chores, walking the dog, emptying the dishwasher, walking to the mailbox, etc.

The more tired you are from lack of sleep due to chronic stress, the more you tend to sit on your butt or lay on the couch. Over time, the reduction in your activity level throughout the day can cause weight gain and poor health. The less you sleep, the less likely you are to move around, and the less you move around, the less energy you use and the lower your metabolism will be.

Additionally, the more tired you are, the more likely it is that you won’t want to work out and/or won’t be able to put as much into your exercise or training sessions which lowers the number of calories your burn from exercise or EAT.

The exercise activity thermogenesis or EAT is the amount of energy it takes to engage in intentional, structured physical exercise.

Another key reason that your metabolism might decrease from stress related changes to your sleep is muscle loss. If you skip your strength training sessions because you’re tired from not sleeping and/or a reduction in the amount of protein consumed to support it.

The more stressed an anxious you are, the more motivated you’ll be to do something you THINK will make you feel better which very often means scrolling or mindlessly watching TV instead of working out. So the more stressed you are the harder it is to redirect your motivation toward your goals.


People grossly underestimate how much high stress levels can keep them from losing body fat. Stress creates a cascade effect that makes it harder to adhere to the healthy behaviors and regular exercise routines you hope to adopt.

Stress also interferes with sleep. Ensuring that you maintain an adequate level of sleep throughout your life is critical for health and reducing stress related weight gain because it:

  • promotes optimal metabolism;
  • promotes balance among the hormones responsible for hunger and appetite;
  • reduces the chances that you’ll make food choices that don’t support your long-term goals; and
  • makes it much easier to be active and exercise.

On the other hand, lack of sleep decreases your insulin sensitivity, turns up your appetite, and makes you more likely to store fat – particularly visceral fat (aka belly fat).

Moral of the story: prioritize stress management and sleep.

Daily habits to manage stress

Good stress management skills make it easier to exercise regularly which is a key component of preserving lean muscle mass, weight control, lowering high blood pressure, preventing heart disease, and maintaining healthy blood sugar levels.

No matter how poor your sleep is, consider at least getting out for a brisk walk.



Delhanty PJD, van der Lely AJ (eds): How Gut and Brain Control Metabolism. Front Horm Res. Basel, Karger, 2014, vol 42, pp 59-72. doi: 10.1159/000358858.

Hirotsu C, Tufik S, Andersen ML. Interactions between sleep, stress, and metabolism: From physiological to pathological conditions. Sleep Sci. 2015 Nov;8(3):143-52. doi: 10.1016/j.slsci.2015.09.002. Epub 2015 Sep 28. PMID: 26779321; PMCID: PMC4688585.

Khatib, H., Harding, S., Darzi, J. & Pot, G. (2017). The effects of partial sleep deprivation on energy balance: a systematic review and meta-analysis. European Journal of Clinical Nutrition, 71, 614–624.

Patel, S. R., Blackwell, T., Redline, S., Ancoli-Israel, S., Cauley, J. A., Hillier, T. A., . . . Stone, K. L. (2008). The association between sleep duration and obesity in older adults. International Journal of Obesity, 32(12), 1825–1834.

Shechter, A., Rising, R., Wolfe, S., Albu, J. B., & St-Onge, M.-P. (2014). Postprandial thermogenesis and substrate oxidation are unaffected by sleep restriction. International Journal of Obesity, 38(9), 1153–1158. http://doi.org/10.1038/ijo.2013.239.

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Hi, I'm Alison

I’m the Founder + CEO of Miles To Go Athletics.

My own journey has taken me from always-injured-and-in-pain-farthest-thing-from-an-athlete in my 30s to ultramarathoner + competitive weightlifter in my 40s and beyond. So I firmly believe that athleticism is accessible to EVERYONE and is actually the key to better quality of life.

My team + I are here to help you stop putting your life on hold due to pain, injuries, and “getting old” and instead get back to the things you really want to be doing – like being active with friends & family, chasing bucket list goals, and feeling badass at any age.

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