Emotional Responses

Regular  leisure-time  physical  activity  provides  a boost to positive emotions: Individuals who exercise  are  routinely  found  to  have  lower  levels  of depression, anxiety, stress, and hostility. Moreover, programs of exercise have also been shown to be an effective treatment for depression, with similar findings emerging for anxiety disorders. This entry focuses on the nature of the link between exercise and emotion, explicating what is known about the range,  limits,  and  mechanisms  behind  emotional responses to exercise.

Exercise Intensity and the Time Course of Emotional Responses

The  positive  emotional  effects  of  exercise  do  not depend on high-intensity workouts. Positive mood benefits  are  routinely  observed  after  moderateintensity  exercise,  with  benefits  (reductions  in negative  emotions  and  enhancement  of  feelings of well-being) reported within 5 to 10 minutes of completing  exercise.  Positive  emotional  responses also  follow  high-intensity  exercise,  but  may  be delayed by almost a half hour. This delay in positive mood may be a product of the negative moods that are induced by higher intensity or emotionally taxing workouts so that the experience of positive mood benefits from exercise must await recovery from  the  negative  mood  induction  brought  by intense  exertion.  Indeed,  one  prominent  determinant  of  negative  moods  during  exercise  is  exertion beyond the ventilatory threshold—commonly reached  when  one  has  difficulty  talking  during exercise.  Also,  during  exercise,  more  negative moods in response to feelings of physical exertion are  reported  by  sedentary  individuals,  those  who are  more  sensitive  exercising  in  front  of  others (secondary to concerns that others may judge their appearance negatively), and those who tend to fear sensations  of  emotional  arousal  (termed  anxiety sensitivity). Mood during exercise is of particular importance  for  the  maintenance  of  leisure-time physical  activity;  negative  mood  emerging  during exercise appears to be a powerful predictor of exercise adherence 6 and 12 months later. In short, more feelings of pleasure during exercise translate into higher rates of exercise over the longer term.

Changes in Depression

The beneficial mood effects of exercise are reliable enough that programmed exercise has emerged as a treatment for depression. Numerous clinical trials indicate that depressed psychiatric patients, as well as  individuals  depressed  due  to  medical  or  other stressors,  can  successfully  use  exercise  as  a  treatment.  In  these  treatment  trials,  moderate  exercise (frequently  walking  for  30  to  40  minutes)  is  prescribed 4 to 5 times a week. Results of this exercise can rival that for antidepressant medications when responses  are  evaluated  after  3  to  4  months  of treatment. Exercise also appears to offer benefit to depressed outpatients who have failed to respond to previous trials of antidepressant medication. As such, programs of regular exercise can be considered an empirically supported treatment for clinical depression,  as  well  as  a  strategy  for  nonclinically depressed individuals to boost their mood.

Changes in Anxiety

As  indicated  by  almost  50  studies,  programs  of moderate exercise can also significantly reduce anxiety and stress. This evidence comes from studies of adults  challenged  by  medical  conditions  or  other specific  stressors,  studies  of  the  elderly,  studies of  adults  in  the  general  population,  and  studies of  psychiatric  samples.  Again,  in  the  context  of well-controlled  clinical  trials,  results  of  exercise programs for anxiety rival those found for antidepressant medications. A program of regular exercise has also been shown to extend the benefits offered by cognitive behavioral treatment for anxiety.

Type of Exercise and Mood Change

The question of whether the mood benefits of exercise depend on dose (frequency, intensity, duration) or exercise type (aerobic training vs. strength training) has been examined only in a handful of studies. These studies show that there is no reason to discourage people from focusing on activities such as weight training or calisthenics for mood improvement instead of pure aerobic activity. That is, while the  evidence  base  is  strong  for  aerobic  training, such  as  walking,  running,  or  biking,  the  studies that  have  compared  aerobic  training  to  strength training have tended not to find meaningful differences.  Whether  more  is  better  is  also  not  entirely clear in the case of exercise for mood and anxiety. Results of studies examining the effects of exercise on anxiety, for example, indicate that the amount of  change  in  anxiety  reaches  a  peak  at  a  dose  of exercise  that  is  roughly  1.5  times  higher  than  the public health recommendation for exercise, which is  30  minutes  of  moderate  exercise  on  5  days  of the  week.  At  doses  higher  than  that,  the  anxiety reduction benefits of exercise tended to decrease.

Exercise, Brain Physiology, and Mood Changes

Exercise  brings  about  a  cascade  of  brain  activity,  with  current  research  supporting  a  number of mechanisms behind the positive mood changes with  exercise.  Animal  studies  provide  reliable evidence  that  exercise  alters  some  of  the  same neurochemical systems presumed to underlie pharmacologic  treatments  for  depression  and  anxiety. Specifically,  exercise  appears  to  modulate  serotonergic and noradrenergic activity in the brain, with some  emerging  evidence  for  γ-aminobutyric  acid (GABA) modulation as well.

Acute  aerobic  exercise  has  been  shown  to increase brain-derived neurotrophic factor (BDNF) levels in both healthy individuals as well as those with psychiatric disorders. BDNF is a neurotrophin involved  in  brain  neuroplasticity,  differentiation and  survival  of  neurons  in  both  the  central  and peripheral nervous system; adequate BDNF levels appear  to  be  an  important  factor  in  the  maintenance  of  normal  cognitive  function  and  mood. Low  BDNF  has  been  associated  with  depression and  anxiety,  and  antidepressant  medications  tend to  enhance  BDNF  levels.  As  such,  BDNF  is  considered as having a potential role in antidepressant activity, perhaps including the antidepressant and antianxiety effects of aerobic exercise.

Although  endorphin  activity  has  been  considered  a  correlate  of  the  runner’s  high  that  may occur after prolonged exercise, at the present time there are several lines of evidence suggesting that endorphin  activity  does  not  explain  the  mood effects brought by moderate exercise.

Finally, atrial natriuretic peptide (ANP) is a peptide hormone that inhibits hypothalamic pituitary adrenocortical  activity  and  may  have  anxiolytic properties. Importantly, submaximal and maximal exercise bouts significantly increase ANP concentrations,  with  early  work  linking  these  changes to  anxiety  reductions,  raising  the  possibility  that ANP changes may mediate some of the antianxiety effects of exercise.

Exercise to Buffer the Negative Effects of Stress on Mood and Anxiety

Among  other  biological  and  psychological  processes,  attention  has  been  paid  to  reduced  stress reactivity as an additional mental health benefit of exercise. The idea is that exercise may help individuals better modulate the kind of stressors that are so often the trigger for the development of mood and  anxiety  problems.  Several  studies  have  now shown  that  trained  individuals  show  less  physiological (e.g., heart rate, blood pressure, cortisol) and  psychological  (e.g.,  anxiety,  tension,  sadness) reactivity when exposed to psychological stressors as  compared  with  their  untrained  counterparts. Importantly, research also shows that these protective effects are evident with single exercise sessions. That is, people tend to be less bothered by stressors when these stressors are preceded by exercise. In addition to getting protection against the development  of  chronic  mood  and  anxiety  problems, these observations suggest that people may notice meaningful immediate mood benefits with regular exercise.

Overexercise and Negative Mood

Although there are anecdotal reports of the emergence  of  depression-like  conditions  from  overexercise in humans (and anxiety-like reactions from overexercise in rodents), there has not been systematic study of these effects. What is more certain is that strenuous exercise may lead to a plummeting mood  during  the  exercise  session,  and  that  these mood  changes  may  make  adherence  to  exercise more  difficult.  Also,  given  the  substantial  delay between  exercise  and  improvement  in  fitness  or shape goals, the process of regular exercise in pursuit of weight reduction or shape improvement is a daunting enterprise. Attending to the emotional benefit brought by exercise offers exercisers a more contingent  (tightly  time-linked)  positive  outcome for their exercise efforts.

Conclusion

Evidence  from  a  variety  of  sources  provides  justification  for  prescribing  exercise  as  a  mood  and anxiety management strategy. The mood and anxiety benefits of exercise are apparent immediately following exercise bouts, particularly among individuals  who  experience  significant  distress.  For these  people  in  particular,  exercise  training  programs that help them establish a habit of repeated (moderate  intensity)  exercise  sessions  every  week can  provide  long-term  mood  benefits  that  rival those  provided  by  established  pharmacological and psychological treatments.

References:

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  2. Ekkekakis, P., Parfitt, G., & Petruzzello, S. J. (2011). The pleasure and displeasure people feel when they exercise at different intensities: Decennial update and progress towards a tripartite rationale for exercise intensity prescription. Sports Medicine, 41, 641–671.
  3. Herring, M. P., Puetz, T. W., O’Connor, P. J., & Dishman, R. K. (2012). Effect of exercise training on depressive symptoms among patients with a chronic illness: A systematic review and meta-analysis of randomized controlled trials. Archives of Internal Medicine, 172, 101–111.
  4. Otto, M. W., & Smits, J. A. J. (2011). Exercise for mood and anxiety: Proven strategies for overcoming depression and enhancing well-being. New York: Oxford University Press.
  5. Rimer, J., Dwan, K., Lawlor, D. A., Greig, C. A., McMurdo, M., Morley, W., et al. (2012). Exercise for depression. Cochrane Database of Systematic Reviews, 7, CD004366.
  6. Wipfli, B. M., Rethorst, C. D., & Landers, D. M. (2008). The anxiolytic effects of exercise: A meta-analysis of randomized trials and dose-response analysis. Journal of Sport & Exercise Psychology, 30, 392–410.

 

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