**2. Why does exercise help with PTSD and emotional disorders?**

The short answer to this question is that no one knows for sure why exercise is beneficial in reducing PTSD and the anxiety and depression that accompany this disorder. There are a number of hypotheses, none of which are universally accepted.

#### **2.1 Thermogenic hypothesis**

This hypothesis proposes that exercise creates an elevation in body temperature and this has a beneficial impact on emotional states. Specifically, aerobic forms of exercise are said to raise the temperature of brain regions such as the brain stem and this produces a tranquilizing effect along with muscle tension reduction. The hypothesis has specifically been used to explain anxiety reduction rather than depression and PTSD. However, given that PTSD was formerly classified as an anxiety disorder and anxiety is a major component of PTSD, it stands to reason that exercise would have a beneficial impact on PTSD. One of the difficulties with the thermogenic hypothesis is that temperature elevation might be an intervening variable that has little to do with the beneficial emotional impact of exercise. For example, it may be that exercise increases temperature but also alters

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*The Role of Exercise in Reducing PTSD and Negative Emotional States*

**2.2 The endorphin and endocannabinoid hypotheses**

have carefully examined the data from empirical studies.

neurochemistry and it is the latter that produces the benefit, not temperature elevation per se. From this perspective temperature plays a correlational rather than a causal role. Additionally, living in a warm environment has not been shown to reduce depression, anxiety, or PTSD nor does having a fever, which also increases internal body temperature. The thermogenic hypothesis does not appear to have held up well as an explanation for the beneficial effects on emotion resulting from

Perhaps the most popular explanation for the positive impact on mood that results from exercise is the endorphin hypothesis. This hypothesis is based on the observation that following vigorous exercise of one half hour or more, there is an elevation of a special endogenous opiate (*B*, or beta, endorphin). This endogenous or body produced opiate is released through exercise and is said by some to be responsible for the "runners high," an elevation of mood following running or jogging or extended periods. The endorphin hypothesis is not without its critics who

One such study compared a jogging group to a relaxation group that did not engage in exercise to a group that did back stretches. The moods that were examined were anger, tension, energy level, calmness, positive mood, depression and others. While all groups produced positive emotional changes there were no differences among the groups. If beta-endorphin is released through exercise, the non-exercise groups should not have shown positive changes and yet they did. Clearly something other than, or in addition to endorphins must be responsible for positive emotional

A further critique of the endorphin hypothesis is that circulating endorphin levels are not reflective of brain endorphin levels and endorphins cannot cross the blood brain barrier. So even if circulating or peripheral endorphin levels increased, this should not have an impact on brain mediated emotional states. A further critique of the endorphin hypothesis is that when the endorphin blocking substance naloxone, an opiate antagonist, is provided to those experiencing the runners high, the elevation in mood is not diminished. If endorphins were causal to exercise induced mood changes, one would expect a significant deterioration in mood fol-

It may be of some significance to note here that a recent alternative to the endorphin hypothesis has come to be known as the *endocannabinoid hypothesis*. Endocannabinoids are bodily produces substances that are similar in action to that of tetrahydrocannabinol (THC), the active constituent in marijuana. Using trained male college students running on a treadmill or cycling on a stationary bike for 50 minutes at 70–80% of maximum heart rate, elevations of endocannabinoids were detected in blood plasma. Because activation of the endocannabinoid system reduces pain sensations, it has been suggested that this might be what is behind the runners high and alterations of mental and emotional processes [10]. Owing to the presence of cannabinoid receptors in the skin, lung, and muscle, it has been suggested that there may be a role for endocannabinoids in producing analgesic effects through exercise. Unlike the endorphin hypothesis where it was noted that endorphins do not cross the blood brain barrier, cannabinoids do appear to operate both centrally (i.e., in the central nervous system) and in the peripheral nervous system. Cannabinoids are reported to reduce anxiety, alter attention, and impair working memory, much like THC does. So, although research is in the early phases, endocannabinoids have been proposed as an alternative to endorphins as the possible mediator of the runners high, analgesic effects and beneficial psychological effects of exercise. The

*DOI: http://dx.doi.org/10.5772/intechopen.81012*

exercise.

effects of exercise.

lowing naloxone injection.

*Psychology of Health - Biopsychosocial Approach*

the reductions increased over time.

traumatic experiences that such abuse usually produces.

beneficial effects on negative emotional states.

**2.1 Thermogenic hypothesis**

intervention rather than using varied forms of more intense aerobic activity. In this study, participants completed a 5 week baseline and then an intervention which involved 25 minutes sessions of exercise which included: 1 minute of slow leisurely walking (warm up), 23 minutes of moderated intensity walking, and 1 minute of slow leisurely walking (cool down). Heart rates were maintained at 60–90% of maximum. By keeping the intervention unvaried and structured, the hope was to make the study more precise than earlier conducted investigations. The majority of participants showed statistically significant reductions in PTSD symptoms from baseline to post-intervention. There was also a reduction in trauma related stress. Results of anxiety and depression measures were not as clear cut as those from PTSD and this may have been due to the fact that initial levels were not overly high and therefore significant reductions were less likely to occur. Like previous studies, the reductions in PTSD were primarily maintained in follow-up and in some cases

The authors concluded that aerobic exercise interventions might be appropriate for youngsters who demonstrate difficulty with expressing their emotions verbally as is required in traditional CBT type therapies. In addition, aerobic exercise as an intervention for PTSD may be more appropriate than exposure therapies, which is more likely to be tolerated in teens with concentration problems, self-control difficulty, and with histories of sexual-abuse and the avoidance of discussing their

A study of adolescent females [9] suggested that peer pressures related to social acceptance significantly affect the high level of anxiety in this group. Issues such as wearing fashionable clothes, having a boyfriend, doing well in school, being popular etc. were factors upon which their peers judged their merit. In this study, individuals in the exercise group participated in 50 minute dance classes, four times a week, for 4 weeks. The classes followed a dance routine to elevate heart rate to 160 beats per minute and ended with a cool-down to bring the heart rate down to 100 beats per minute. Results of the study showed clear benefits in terms of anxiety reduction by engaging in the aerobic dance routine. Thus it appears that a variety of exercises from treadmills, to walking, to kickboxing to dance and others can have

**2. Why does exercise help with PTSD and emotional disorders?**

The short answer to this question is that no one knows for sure why exercise is beneficial in reducing PTSD and the anxiety and depression that accompany this disorder. There are a number of hypotheses, none of which are universally accepted.

This hypothesis proposes that exercise creates an elevation in body temperature and this has a beneficial impact on emotional states. Specifically, aerobic forms of exercise are said to raise the temperature of brain regions such as the brain stem and this produces a tranquilizing effect along with muscle tension reduction. The hypothesis has specifically been used to explain anxiety reduction rather than depression and PTSD. However, given that PTSD was formerly classified as an anxiety disorder and anxiety is a major component of PTSD, it stands to reason that exercise would have a beneficial impact on PTSD. One of the difficulties with the thermogenic hypothesis is that temperature elevation might be an intervening variable that has little to do with the beneficial emotional impact of exercise. For example, it may be that exercise increases temperature but also alters

**72**

neurochemistry and it is the latter that produces the benefit, not temperature elevation per se. From this perspective temperature plays a correlational rather than a causal role. Additionally, living in a warm environment has not been shown to reduce depression, anxiety, or PTSD nor does having a fever, which also increases internal body temperature. The thermogenic hypothesis does not appear to have held up well as an explanation for the beneficial effects on emotion resulting from exercise.
