By Dr. Mercola
A workout can be a great way to unwind after a stressful day, but ruminating over that unpleasant meeting with your boss may make your exercise session less effective.
New research suggests that if your brain is tired, the rest of your body may be tired as well, because the two go hand in hand. Why is it that mental and physical fatigue are so closely connected?
Part of the answer is that physical and mental fatigue affect the same region of your brain—the anterior cingulate cortex. If that part of your brain is broadcasting "my brain is fried" signals at the end of the day, then it's likely your muscles will be tired even before you head for the gym.
Exercising after the occasional harrowing day is unavoidable, but if you are chronically stressed, you could be seriously derailing your fitness goals. A new study in the Journal of Sport and Exercise Psychology1 found that mental burnout significantly affected physical performance.
Runners were intentionally stressed by being forced to complete a difficult computer test immediately before a 1.86-mile race (3,000-meters). The race times for runners who had taken the test were about 15 seconds slower than for the runners who hadn't taken it.
But the deleterious effects of stress are actually farther reaching.2, 3 In this article, we will review 10 ways stress can sabotage your fitness efforts. If you walk around in a semi-permanent state of overwhelm, perhaps your next workout should consist of several rounds of high-intensity stress management—instead of crunches or curls!
1. Stress Impairs Working Memory
Stress affects the part of your brain that deals with both short-term and long-term memory, and "working memory." Working memory is what you use when you must consider multiple pieces of information at once (e.g. decision-making).
The process of thinking, perceiving, and evaluating requires your brain to have processing power—much like a computer. The more stress there is in the background, the less processing speed you will have at any given time.4
If your working memory is impaired, as it is with chronic stress, even the simplest tasks become difficult, and athletic performance is no exception.
Whether you are an elite athlete or just engaging in a routine exercise class, if your brain is struggling to process information, then you'll fatigue more quickly—mentally and physically. Making matters worse, when your stress levels are high, impulsivity typically trumps patience, which is not helpful at the gym or anywhere else.
2. Stress Sabotages Concentration
High levels of stress have been shown to negatively affect most aspects of human cognition and perception, including concentration and mental focus. There are two types of attention: external and internal. When you're stressed, you are preoccupied with the source of the stress (internal focus), so you have fewer resources available for the task at hand (external focus).
Take golf, for example. Accurate perception and the ability to pay attention are key to a successful game. But if stress begins to interfere with your focus, your golf game is bound to suffer. There is probably no better example of this than Tiger Woods, whose PGA rank plummeted after his scandalous affair and the resulting media frenzy—undoubtedly related to the major stress he experienced during that period of time.5
3. Stress Impairs Motor Coordination
Stress has been scientifically shown to impair motor control and coordination because it interferes with information processing in your cerebellum, the area of your brain responsible for these functions.
Research published in the Journal of Neuroscience showed that even a single exposure to acute stress affects information processing in your cerebellum.6 Stress is often accompanied by increased muscle tension, which can impede physical performance, increase your risk for injury, and slow down tissue repair.
4. Stress Compromises Visual Acuity
Stress can even interfere with your visual acuity and perception. High stress has been linked with everything from simple eye twitches to temporary blindness. Because your eyes work so closely with your brain, elevated cortisol has negative effects on the way you see things and process visual cues.7 With chronic stress, your adrenaline level stays elevated, potentially causing pressure in your eyes, distorted or blurred vision, tunnel vision, and eye strain. When stressed, your pupils dilate and the muscles around your face tighten, which constricts the blood vessels feeding your eyes. This then contributes to eye strain, headaches, and decreased visual acuity.8, 9
5. Stress Hampers Your Fitness Gains
If your stress level is high, you may not reach your fitness goals as quickly, as Finnish researchers recently discovered. According to Huffington Post:10
"When you stick to a gym schedule, your muscles, heart and lungs adapt over time, making you fitter and stronger. One way experts measure this increase in fitness is by testing your VO2 max, how much oxygen your body uses during a workout. When Finnish researchers monitored 44 people starting a new cycling regimen, those who rated their stress levels highest saw the least improvement in VO2 max in a two-week period, despite doing the same workouts as everyone else."
6. Stress Slows Exercise Recovery
Exercise itself is a form of stress, which triggers changes that make your body stronger. But the system breaks down if you are chronically stressed, as chronic stress impairs your body's ability to respond to acute stress—such as exercise—because its resources are essentially used up.
A Yale study11, 12 involving undergraduate students demonstrates how people with chronic stress take longer to recuperate from one high-impact exercise session. Stress levels were assessed using a psychological tool. An hour after the workout using heavy leg weights, the students with the lowest stress levels had regained 60 percent of their leg strength, whereas the high-stress students had regained only 38 percent.
Researchers attributed the difference to higher levels of cortisol and other stress chemicals, which affect your body's rate of repair. They also postulated that the higher-stress students might have been getting inadequate sleep, eating poorly, and generally neglecting basic self-care, which would have compromised their bodies' repair processes.
Similar results were found in a Journal of Strength and Conditioning Research study, in which individuals with higher stress felt more tired and sore 24 hours after a tough workout than individuals feeling less stressed.13 These studies and others confirm that microscopic cellular processes that repair damage within your body are mediated by your state of mind. So if you're stressed, recovery from exercise will take longer—because so little is left in your tank for repair and recovery. In the words of Dr. Lissa Rankin, author of Mind Over Medicine:14
"Our bodies know how to fix broken proteins, kill cancer cells, retard aging, and fight infection. They even know how to heal ulcers, make skin lesions disappear and knit together broken bones. But here's the kicker—those natural self-repair mechanisms don't work if you're stressed!"
7. Stress Raises Your Risk for Injury
Another downside to exercising under stress is that you're more likely to hurt yourself. Research has shown that a high degree of major life stresses (moving, divorce, death of a family member, etc.) or a high amount of daily hassles (getting a flat tire or a speeding ticket, losing your cell phone, etc.) can increase your risk for exercise injury. This is thought to result from attentional deficits and increased muscle tension.15, 16
According to Sports Injury Bulletin:17
"Past research has seen the relationship between athletic injuries and psychological factors as essentially stress-related. In this sense, stress is predicted to produce increased state anxiety and consequently alterations in attentional focus and muscular tension... Stress can cause attentional narrowing which results in important peripheral cues being missed."
8. Stress Seriously Impedes Weight Loss
It is well known that stress can lead to increased cardiovascular risk, but it can also lead to increased belly fat and weight gain. Stress alters the way fat is deposited because of the specific hormones and other chemicals your body produces—a primary one being cortisol. When stress keeps your cortisol levels elevated, your body stores more energy as fat.
In a Kaiser Permanente study,18 researchers put 472 obese adults on a diet and exercise program designed to help them lose 10 pounds despite being told to eat a low fat diet. The participants were first assessed for their level of stress. Researchers found that the participants with the highest stress were the least likely to hit their weight loss target. Even more remarkable was that the participants who became more stressed during the study actually gained weight, rather than losing it. Adding poor sleep (less than six hours per night) to higher stress slashed participants' weight loss in half.
9. Stress Kills Motivation
Does your motivation to exercise fly out the window when you've had a particularly stressful day? According to Huffington Post,19 Yale researchers looked at all of the studies they could find on stress and exercise habits, and three-quarters showed that people under pressure tend to slack off on physical activity and spend more time sedentary. In one of the studies reviewed, participants were 21 percent less likely to work out regularly during times of stress, and 32 percent less likely to stick to their fitness schedule over the following four years. A 2014 study20 in Sports Medicine came to the same conclusion—stress is likely to thwart your efforts at being physically active. This phenomenon proved especially true for older adults and those newer to their fitness schedules. Not exercising when your stress level rises is particularly unfortunate, because exercise is such an excellent stress-reduction tool.
10. Stress Depletes Emotional Resources
If your fuse is shorter when you're stressed out, you're not alone. Under stress, most people have fewer emotional "resources" and feel less resilient to life's normal ups and downs. The same can be said for sleep deprivation. If you're stressed, you are more vulnerable to the psychological effects of poor performance and mood swings, and more likely to experience discouragement and fluctuating self-esteem. All of this can certainly thwart your fitness goals.21
This emotional vulnerability likely relates to the effects stress has on your brain—stress literally shrinks it! Yale researchers22, 23 examined 103 healthy adults who had experienced major life stresses within the previous year, assessing their brain volume with MRI scans. They concluded that major stress, combined with ordinary everyday irritations, actually shrink your "gray matter," and this shrinkage affects emotions, self-control, and heart rate. It follows that this could have psychological effects that ripple into nearly every aspect of your life, including your health and fitness efforts.
Stress Affects MUCH More Than Your Waistline
In spite of the above, an ineffective workout is NOT the worst thing that could happen when your stress level is out of control. For example, as stress rises, so do your numbers of white blood cells, and this can lead to plaque rupture, heart attack, or stroke. Stress hormones also disperse bacterial biofilms from the walls of your arteries, which may also trigger a heart attack. Chronic stress is linked with memory impairment, and elevated stress hormones can speed up short-term memory loss in older adults and may trigger the onset of Alzheimer's disease.
You are more vulnerable to the adverse effects of stress if you feel like you have no control, feel like things are getting worse, and have inadequate social support. Stress drives up inflammation. When your stress hormones are elevated, your heart and respiratory rates increase to prepare you to fight or flee from the perceived threat. Your immune system is temporarily suppressed.
When stress becomes chronic, your immune system becomes less sensitive to cortisol, and since inflammation is partly regulated by this hormone, this amplifies your inflammatory response. Inflammation plays a role in most chronic diseases, which is why stress is such a major factor in many chronic health problems:
Cardiovascular disease ||Type 2 diabetes ||Cancer
|Frequent colds and flu ||Sexual dysfunction and infertility ||Neurological diseases
|Insomnia and fatigue||Depression and anxiety||Food allergies and sensitivities
|Slower metabolism and weight gain ||Autoimmune problems||Digestive problems and dysbiosis
Stress-Busting Tools and Tips
It's difficult to stay committed to your goals when you're consumed by stress, which is why regular stress management is very important. If your stress levels are high, the solution is NOT to skip your workout—after all, exercise itself is a powerful tool for combating stress. Instead, do whatever it takes to get yourself to the gym, but make adjustments to your intensity and allow more time for recovery between sessions.
Be mindful of what you're doing so that you don't injure yourself. Pay extra attention to your dietary choices and sleep, and give yourself a little extra self-kindness. Besides working out, there are many other effective stress reduction techniques you can try. What works for you may not work for someone else—one person may enjoy meditating, while another may feel calmer after kickboxing! You'll just have to find what works best for you. I have provided some ideas in the following table.
Effective Stress-Reducing Tips and Tools
|Adjust your expectations
||Learn how to say "no" and delegate
||Express feelings instead of bottling them up
|Avoid stressful people and situations
||Be flexible and willing to compromise
||Pick your battles carefully
|Focus on the positive
||Laugh at yourself
|Have more fun
||Ask for help when you need it
||Address cognitive distortions
|Have a good cry
||Spend time in nature
||Address conflicts with others
|Connect with others
||Manage time better
EFT: The Stress-Busting Tool That Tops My List
One of my favorite stress-busting tools is EFT, or Emotional Freedom Technique. EFT allows you to reprogram your body's reactions to the unavoidable stressors of everyday life, making it easier to take them in stride. Studies have shown EFT to be a powerful stress reduction tool. In 2012, a triple blind study24 found that EFT reduced cortisol levels and symptoms of psychological distress by 24 percent—more than any other intervention tested. EFT is easy to learn and once you do, it will always be at your fingertips—whenever and wherever you need it. You can even use EFT to get yourself to the gym!
For more information on how to use EFT for stress, please refer to our previous article. You can also view the demonstration above.