Health Benefits of Exercise

Exercise increases skin graft resistance to rejection

Regular exercise reduces risk of various chronic diseases and can prevent the development and recurrence of cancer, making it a promising nonpharmacological modulator of disease. Yet the effect of regular exercise on solid organ transplant outcome remains uncertain. Using a model of voluntary wheel-running exercise and skin transplantation in mice, we hypothesized that exercise strengthens the alloimmune response, leading to an increased rate of rejection. Instead, we found that regular exercise in mice resulted in prolonged graft survival, with mean allograft survival time increasing by almost 50%. We observed this graft survival extension in exercised mice despite evidence of a slightly enhanced alloimmune response, comprised of increased proliferation of alloreactive CD4⁺ T cells, as well as increased interferon-γ production by these cells. Exercise was not associated with significant changes in numbers of conventional CD4⁺ or CD8⁺ T cells, NK cells, or Foxp3⁺ regulatory T cells. In conclusion, our study suggests that exercise increases skin graft resistance to a similar or slightly higher level of alloimmunity and supports regular exercise as an important beneficial pursuit for transplant recipients.

The New Runner's High? Examining Relationships Between Cannabis Use and Exercise Behavior in States With Legalized Cannabis

Scientific literature examining cannabis use in the context of health behaviors, such as exercise engagement, is extremely sparse and has yielded inconsistent findings. This issue is becoming increasingly relevant as cannabis legalization continues, a situation that has been associated with increased initiation of use among adults, and increased potency of available products in legalized states. Physical activity is among the most important health behaviors, but many Americans do not meet minimum exercise recommendations for healthy living. Common issues surrounding low exercise rates include inadequate enjoyment of and motivation to exercise, and poor recovery from exercise. It is unclear whether cannabis use shortly before and/or after exercise impacts these issues, and whether this co-use affects exercise performance. The present online survey study examines attitudes and behaviors regarding cannabis use with exercise among adult cannabis users living in states with full legal access (N = 605). Results indicated that the majority (81.7%) of participants endorsed using cannabis concurrently with exercise, and those who did tended to be younger and more likely to be males (p < 0.0005 for both). Even after controlling for these differences, co-users reported engaging in more minutes of aerobic and anaerobic exercise per week (p < 0.01 and p < 0.05, respectively). In addition, the majority of participants who endorsed using cannabis shortly before/after exercise reported that doing so enhances their enjoyment of and recovery from exercise, and approximately half reported that it increases their motivation to exercise. This study represents an important step in clarifying cannabis use with exercise among adult users in states with legal cannabis markets, and provides guidance for future research directions.

Predictors of Mindfulness Meditation and Exercise Practice, from MEPARI-2, a randomized controlled trial

Objectives

Health-supporting behaviors can be challenging to initiate and maintain. Data from the MEPARI-2 randomized trial were used to assess predictors of sustained exercise and meditation practice.

Methods

Adults aged 30 to 69 years not exercising regularly and without prior meditation training were randomized to 8-week trainings in mindfulness meditation, moderate intensity exercise, or observational control, and monitored for 8 months. Exercise participants reported day-to-day minutes of moderate and vigorous activity; mindfulness meditation participants reported minutes of informal and formal practice. Demographic characteristics and psychosocial factors were assessed as predictors of practice. Growth mixture modeling was used to identify higher and lower practice subgroups.

Results

413 participants (75.8% female; mean (SD) age 49.7 (11.6) years) were randomized to exercise (137), mindfulness meditation (138), or control (138), with 390 (95%) completing the study. Seventy-nine percent of exercisers and 62% of meditators reported ≥150 minutes/week practice for at least half of the 37 weeks monitored. Self-reported minutes of mindfulness meditation and/or exercise practice were significantly (p<0.01) predicted by baseline levels of: general mental health, self-efficacy, perceived stress, depressive symptoms, openness, neuroticism, physical activity, smoking status, and number of social contacts. Growth mixture modeling identified subsets of people with moderate (100-200 min/week) and high (300-450 min/week) levels of self-reported practice for both mindfulness meditation (62% moderate; 38% high) and exercise (71% moderate; 29% high).

Conclusions

In this sample, participants randomized to behavioral trainings reported high levels of practice sustained over 37 weeks. Baseline psychosocial measures predicted practice levels in expected directions.

Voluntary Wheel Running: A Useful Rodent Model for Investigating the Mechanisms of Stress Robustness and Neural Circuits of Exercise Motivation

Despite evidence that exercise reduces the negative impacts of stressor exposure and promotes stress robustness, health and well-being, most people fail to achieve recommended levels of physical activity. One reason for this failure could be our fundamental lack of understanding the brain motivational and motor circuits underlying voluntary exercise behavior. Wheel running is an animal model used to reveal mechanisms of exercise-induced stress robustness. Here we detail the strengths and weakness of wheel running as a model; and propose that running begins as a purposeful, goal-directed behavior that becomes habitual with continued access. This fresh perspective could aid in the development of novel strategies to motivate and sustain exercise behavior and maximize the stress-robust phenotype.

Rewiring the Addicted Brain Through a Psychobiological Model of Physical Exercise

Drug addiction is a worldwide public health problem, resulting from multiple phenomena, including those both social and biological. Chronic use of psychoactive substances has been shown to induce structural and functional changes in the brain that impair cognitive control and favor compulsive seeking behavior. Physical exercise has been proven to improve brain function and cognition in both healthy and clinical populations. While some studies have demonstrated the potential benefits of physical exercise in treating and preventing addictive behaviors, few studies have investigated its cognitive and neurobiological contributions to drug-addicted brains. Here, we review studies in humans using cognitive behavioral responses and neuroimaging techniques, which reveal that exercise can be an effective auxiliary treatment for drug addictive disorders. Moreover, we describe the neurobiological mechanisms by which exercise-induced neuroplasticity in the prefrontal cortex improves executive functions and may decrease compulsive behaviors in individuals prone to substance use disorders. Finally, we propose an integrative cognitive-psychobiological model of exercise for use in future research in drug addiction and practical guidance in clinical settings.

An Update on the Role of Cardiorespiratory Fitness, Structured Exercise and Lifestyle Physical Activity in Preventing Cardiovascular Disease and Health Risk

The cardiovascular disease (CVD) pandemic has placed considerable strain on healthcare systems, quality of life, and physical function, while remaining the leading cause of death globally. Decades of scientific investigations have fortified the protective effects of cardiorespiratory fitness (CRF), exercise training, and physical activity (PA) against the development of CVD. This review will summarize recent efforts that have made significant strides in; 1) the application of novel analytic techniques to increase the predictive utility of CRF; 2) understanding the protective effects of long-term compliance to PA recommendations through large cohort studies with multiple points of assessment; 3) and understanding the potential harms associated with extreme volumes of PA.

Medial habenula maturational deficits associate with low motivation for voluntary physical activity

The habenula is a small, diencephalic structure comprised of distinct subnuclei which receives inputs from the limbic forebrain and sends projections to various regions in the midbrain, making this region well positioned to influence reward and motivation. Genetic ablation of the dorsal medial habenula is known to decrease voluntary wheel-running in mice. However, the extent to which the medial habenula (MHb) mediates wheel-running motivation in the context of high or low motivation for voluntary physical activity remains to be determined. In so, we utilized 5-week-old female rats selectively bred to voluntarily run high (HVR) or low (LVR) distances in order to determine if inherent differences in medial habenula maturation accompany inherent differences in wheel-running motivation. We report a significantly higher expression of genes associated with MHb development (Brn3a, Nurr1, Tac1, and Kcnip) in HVR versus LVR rats. Furthermore, there was a positive correlation between Brn3a and Nurr1 expression and run distance in HVR, but not LVR rats. Similarly, NeuN and Synapsin 1, markers of neuronal maturation, were higher in HVR compared to LVR rats. Lastly, dendritic density was determined to be higher in the MHb of HVR versus LVR rats, while LVR rats showed a higher percentage of thin spines, suggesting a higher prevalence of immature dendrites in LVR rats. Taken together, the above findings highlight the involvement of MHb in driving the motivation to be physically active. Given pandemic levels of global physical inactivity, the role of the MHb offers a novel potential to improve our global health.

JNK regulates muscle remodeling via myostatin/SMAD inhibition

Skeletal muscle has a remarkable plasticity to adapt and remodel in response to environmental cues, such as physical exercise. Endurance exercise stimulates improvements in muscle oxidative capacity, while resistance exercise induces muscle growth. Here we show that the c-Jun N-terminal kinase (JNK) is a molecular switch that when active, stimulates muscle fibers to grow, resulting in increased muscle mass. Conversely, when muscle JNK activation is suppressed, an alternative remodeling program is initiated, resulting in smaller, more oxidative muscle fibers, and enhanced aerobic fitness. When muscle is exposed to mechanical stress, JNK initiates muscle growth via phosphorylation of the transcription factor, SMAD2, at specific linker region residues leading to inhibition of the growth suppressor, myostatin. In human skeletal muscle, this JNK/SMAD signaling axis is activated by resistance exercise, but not endurance exercise. We conclude that JNK acts as a key mediator of muscle remodeling during exercise via regulation of myostatin/SMAD signaling.

Overexpression of Protein Kinase Inhibitor Alpha Reverses Rat Low Voluntary Running Behavior

A gene was sought that could reverse low voluntary running distances in a model of low voluntary wheel-running behavior. In order to confirm the low motivation to wheel-run in our model does not result from defects in reward valuation, we employed sucrose preference and conditioned place preference for voluntary wheel-access. We observed no differences between our model and wild-type rats regarding the aforementioned behavioral testing. Instead, low voluntary runners seemed to require less running to obtain similar rewards for low voluntary running levels compared to wild-type rats. Previous work in our lab identified protein kinase inhibitor alpha as being lower in low voluntary running than wild-type rats. Next, nucleus accumbens injections of an adenoviral-associated virus that overexpressed the protein kinase inhibitor alpha gene increased running distance in low voluntary running, but not wild-type rats. Endogenous mRNA levels for protein kinase inhibitor alpha, dopamine receptor D1, dopamine receptor D2, and Fos were all only lower in wild-type rats following overexpression compared to low voluntary runners, suggesting a potential molecular and behavioral resistance in wild-type rats. Utilizing a nucleus accumbens preparation, three intermediate early gene mRNAs increased in low voluntary running slices after dopamine receptor agonist SKF-38393 exposure, while wild-type had no response. In summary, the results suggest that protein kinase inhibitor alpha is a promising gene candidate to partially rescue physical activity in the polygenic model of low voluntary running. Importantly, there were divergent molecular responses to protein kinase inhibitor alpha overexpression in low voluntary runners compared to wild-type rats.

Voluntary wheel running improves adipose tissue immunometabolism in ovariectomized low-fit rats

Loss of ovarian hormones is associated with increased adiposity, white adipose tissue (WAT) inflammation, and insulin resistance (IR). Previous work demonstrated ovariectomized (OVX) rats bred for high aerobic fitness (HCR) are protected against weight gain and IR compared to rats bred for low aerobic fitness (LCR) yet wheel running prevents OVX-induced IR in LCR rats. The purpose of this study was to determine whether adipose tissue immunometabolic characteristics from female HCR and LCR rats differs before or after OVX, and whether wheel running mitigates OVX-induced adipose tissue immunometabolic changes in LCR rats. Female OVX HCR and LCR rats were all fed a high fat diet (HFD) (n = 7-8/group) and randomized to either a running wheel or remain sedentary for 11 weeks. Ovary-intact rats (n = 7-12/group) were fed a standard chow diet with no wheel. Ovary-intact LCR rats had a greater visceral WAT inflammatory profile compared to HCR. Following OVX, sedentary LCR rats had greater serum leptin (p<0.001) and WAT inflammation (p<0.05) than sedentary HCR. Wheel running normalized the elevated serum leptin and reduced both visceral (p<0.05) and subcutaneous (p<0.03) WAT inflammatory markers in the LCR rats. Paradoxically, wheel running increased some markers of WAT inflammation in OVX HCR rats (p<0.05), which correlated with observed weight gain. Taken together, HCR rats appear to have a healthier WAT immune and metabolic profile compared to LCR, even following OVX. Wheel running improves WAT health in previously sedentary LCR rats. On the other hand, increased WAT inflammation is associated with adiposity gain despite a high volume of wheel running in HCR rats.

Associations Between Objectively Measured Physical Activity and Executive Functioning in Young Adults

Associations between daily physical activity (PA) and executive functioning have rarely been investigated among young adults. This study examined these associations among 162 university students (74 females and 88 males; mean age = 19.0, SD = 1.1 years). We measured PA objectively, using hip-mounted accelerometers, and assessed executive functioning in a task-switching paradigm. Anthropometrics measurements were gathered using standardized procedures. Through linear regression modeling, we found moderate-to-vigorous physical activity (β = −0.19, 95% CI = [−0.35, −0.03], p = .02) and light physical activity (β = −0.17, 95% CI = [−0.34, −0.01], p = .04) to be associated with smaller global reaction time switch costs. Total PA was not associated with task-switching performance, and there were no statistically significant associations between PA indicators and local switch costs. As both moderate-to-vigorous and light physical activities were associated with better executive function in young adults, there can be important cognitive benefits to remaining physically active.

Physical fitness and levels of physical activity in people with severe mental illness: a cross-sectional study

Background

Physical fitness is a crucial variable in people with severe mental illness as these people could be more independent and improve their job opportunities. The present study compared the physical fitness of physically active and inactive people with severe mental illness.

Methods

Physical fitness was evaluated in sixty-two people with severe mental illness using 11 physical tests that include strength, flexibility, balance and aerobic condition. Significant differences were found between both groups in muscle strength (handgrip test) and balance (single leg balance test and functional reach) with better performance in the group of physically active people.

Results

The results of the present study suggest that physical fitness (strength and balance) is higher in people with severe mental illness who practise regular physical activity that those who are inactive people.

Conclusions

Physical active people may have a reduced risk of falls and fractures due to their higher levels of physical fitness.