In this series, we’re exploring a variety of client scenarios. We describe a few tips from my science-based coaching toolbox to help you help your clients engage fully in a fit lifestyle that allows them to thrive, whatever thriving means in their lives.

• Set the feeling of being overwhelmed aside to focus on the task at hand;
• Stay focused on meaningful goals and a higher purpose, resisting temptations that are in fact “error” messages;
• Recognize that cravings (checking texts, junk food, etc.) and negative emotions fade away like clouds in the sky;

• Be self-compassionate and not indulge the inner critic;
• Find the positive silver linings in stressors and negative emotions, thoughts and events; and
• Detach from a negative emotional weather report to get a strategic perspective. (“Maybe I’m overreacting …”).

A depleted PFC is hijacked easily by:

• A feeling of being overwhelmed caused by a daunting to-do list;
• Cravings for “addictive” foods and drinks;
• The negative self-talk of a mean inner critic, triggering the inner rebel to make an unhealthy choice;
• A negative emotional weather pattern, clouding the ability to notice and savor positive moments; and
• An overdose of stress, leading us to feel out of control.

How can you help your clients improve the function of the PFC and stay confidently in control, happily making healthy choices? Be a great role model, and suggest they experiment with one or more of the following to discover what combination of habits works best:

• Drive. Create a compelling vision and goal for the moment, the day, month or year (e.g., to radiate energy and health) to bring to mind at the moment you have a choice to make, dozens of times each day. Design the vision and goal (e.g., picture, poem or statement) so that it energizes you when you recall it and inspires you to make a healthy choice most of the time.
• Exercise. Over time, regular exercise leads to a strengthening of the PFC and its capacity to manage negative emotions and stress.

• Brain breaks. Take brain breaks where you allow your mind to wander, or move your mind’s attention to your heart through deep breathing — or move your muscles through a few stretches or strength exercises. Even two to five minutes of walking, stair-climbing or yoga will refresh the PFC. Nothing is better than a good night’s sleep, or even a catnap, to hit the PFC’s reset button.
• Self-compassion. Turn your inner critic into your inner friend. Be kind to yourself. Negative self-talk is particularly depleting.
• Mindful practices. Take deep breaths or do short meditations to unhook the mind from the frenzy of out-of-control thoughts and emotions. Create mental pauses when making decisions about eating and exercise to give the PFC a moment to get back into the driver’s seat. Regular meditation also improves PFC function over time.
• Savor and cultivate positive emotions. Positive emotions were designed to be fleeting, like butterflies, in contrast with negative emotions, which move lightning fast and stick like Velcro. Positive emotions improve cognitive function, in contrast with the impairment caused by negative emotions. Cultivate positive emotions (check out your ratio at positivityratio.com) so that you have the cognitive resources to manage or overcome the negative in your life.
• Connect with people you care about. The most powerful positive emotions “lighting up” our brains are those we share with others. Express gratitude for someone’s contribution to your life, do something nice and unexpected for someone, or harvest and celebrate what’s going well with people you care about.

• Nourish your brain. Feed your brain a nice steady dose of glucose, enabled by a good balance of lean protein, healthy fats and complex carbohydrates. A well-nourished brain is a brain that wants to make healthy choices.

Thankfully, the field of neuroscience has caught up with the mind/body practices. Here’s to a world full of high-functioning prefrontal cortexes — calm, positive, energetic, healthy, fit, well-nourished and well-rested.

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The majority of adolescents aged 11–17 years are insufficiently physically active globally, with differences found across sexes and countries. In addition, time spent using digital media, a common sedentary behavior, has increased and sleep duration has decreased among youth in recent decades. Simultaneously, the prevalence of depressive and anxiety disorders has increased among adolescents in many countries.

Achieving higher levels of physical activity, lower levels of sedentary behavior, better sleep quality, adequate sleep duration and shorter sleep latency associate with better mental health and wellbeing among adolescents. Cross-sectional studies often assume movement behaviors represent the causal factor, that is, they affect mental health. However, the association may also be reverse; adolescents with poorer mental health may be less likely to engage in favorable behaviors. For example, a study by Gunnell et al. examined bidirectional relationships between physical activity, screen time and symptoms of anxiety and depression over time during adolescence. They found that greater initial symptoms of depression predicted greater decreases in physical activity, but no other relationship between physical activity, screen time and anxiety or depression were detected.

Despite widespread public attention to the assumed negative consequences of digital media use on mental health, existing research evidence among young people is primarily cross-sectional. In addition, many existing studies do not differentiate between different types of digital use, such as between active use (participatory media use, e.g., chatting, messaging and liking) and passive use (media consumption, e.g., viewing programs), although different types of digital media use may be differentially associated with mental health, and recent studies have questioned the use of total screen time.

Research on movement behaviors, including physical activity, sedentary behavior and sleep, has traditionally concentrated on examining individual behaviors and their associations with health. Current research, however, is moving towards identifying different combinations of these behaviors, which may have important implications for health already during childhood or adolescence. A person-oriented approach seeks to identify unique latent groups within a population, and focuses on profiles across characteristics to describe a certain phenomenon. Recent studies using this approach in movement behavior research have identified several distinct profiles or patterns indicated by sedentary behavior and physical activity among children and adolescents.

The relationship between different combinations of movement behaviors and mental wellbeing among youth remains relatively unstudied until recently. In their two recent studies, Brown et al. identified four distinct movement behavior profiles among adolescents and observed that a profile characterized by high amounts of physical activity and low amounts of digital media use was consistently associated with the highest levels of current mental wellbeing and with lowest depressive symptoms, both currently and one year later. Further, Brown and Kwan showed that replacing 60 minutes of screen time with either moderate-to-vigorous physical activity or sleep associated with better self-esteem and resiliency among adolescents.

In our very recent longitudinal study, we first wanted to examine behavior profiles indicated by leisure-time physical activity and different types of digital media use (active and passive use, gaming and bedtime delay because of digital media use) among 1,500 15-year-old Finnish adolescents. We identified four different behavior profiles. About 30% of adolescents belonged to the “healthiest” behavior profile characterized by moderate digital media use and high physical activity, whereas 23% belonged to the “unhealthiest” behavior profile characterized by high passive digital media use and gaming with low physical activity. Secondly, we wanted to examine whether mental health indicators assessed at 11 years of age predicted belonging to these behavior profiles four years later. After taking into account confounding factors, such as physical activity and digital media use at 11 years of age, symptoms of depression or anxiety did not associate with later behavior profiles. However, higher amount of physical activity and better perception of athletic competence among the 11-year-olds predicted belonging to any other profile than to the “unhealthiest” profile characterized by high passive digital media use and gaming and low physical activity.

Our results suggest that physical activity and related self-esteem may be stronger predictors of future physical activity and digital media use behavior during adolescence than mental health symptoms alone. At present, relatively little is still known about how digital media use, physical activity and sleep behaviors interact among adolescents, or how the interplay of these behaviors and mental health relate with each other over time. Hopefully this area of research will receive further attention to deepen our understanding on the direction of the relationship between movement behaviors and mental health among children and adolescents.

More Mental Health Research & Resources

Elina Engberg, Ph.D., is a postdoctoral researcher and project leader of the SUNRISE Finland Study. She is a member of ACSM's Psychobiology and Behavior Special Interest Group.

During strenuous exercise, the neuromuscular system is repeatedly stressed, causing impairments to occur at various potential sites along the brain-to-muscle pathway. These perturbations cause a reduction in the ability of our muscles to generate force, which can increase our sense of effort, cause us to slow down and reduce our capacity to perform high intensity exercise. There are, globally, two primary causes of this “neuromuscular fatigue.” First, voluntary activation of the muscles by the nervous system can be reduced. Second, contractile function, or the muscle’s intrinsic ability to respond to neural input, can be reduced owing to perturbations occurring within muscle cells. Using neurostimulation methods, the contribution of both the nervous system and muscle to reductions in maximal muscle force-generating capacity can be measured.

In recent years, research has focused on how the characteristics of the aerobic exercise we perform, such as the intensity and duration, influence neuromuscular fatigue and its mechanisms. However, research focused on how the modality of exercise influences the magnitude and mechanisms of neuromuscular fatigue is lacking.

In our study, published in the May 2022 issue of Medicine & Science in Sports & Exercise_®, we compared the effects of the two most common types of whole-body dynamic exercise, running and cycling, on neuromuscular fatigue. To do so, we recruited 17 males trained in both endurance running and cycling, and had them perform running and cycling at a matched intensity (105% of the gas exchange threshold) and duration (three hours) using a crossover design. Neuromuscular function was assessed in the right knee extensor at pre-, mid- and post-exercise, and included isometric maximal voluntary contraction force, voluntary activation, contractile function and alpha-motoneuron excitability.

Our results demonstrated that the magnitude of the decrease in maximal force-generating capacity of the knee extensors was similar between the two modalities. Specifically, maximal force was reduced by ~ 25% following both cycling and running. However, the mechanisms contributing to this force loss were distinct between cycling and running. Specifically, the reduction in muscle force in response to cycling was primarily due to mechanisms residing within the muscle. In contrast, the reductions in response to running were due almost exclusively to impairments in the capacity of the nervous system to activate muscle, concurrent with greater reductions in motoneuron excitability. These results can likely be explained by differences in the mechanical and metabolic demands imposed on the quadriceps during the respective exercise modalities.

An interesting finding was that, despite a substantial reduction in force-generating capacity, contractile function of the quadriceps was well preserved following three hours of running. This emphasizes the important role of the nervous system in contributing to neuromuscular fatigue, with the substantial loss in motoneuron excitability indicating that spinal mechanisms might have been implicated. Moreover, the limited change in contractile function in response to running indicates low metabolic stress. As exercise-induced peripheral adaptations occur in response to the degree of local perturbation, this result has potential implications for adaptations to running and cycling. Our results highlight the importance of aerobic exercise modality in determining the causes of neuromuscular fatigue. 

Callum Brownstein (@CGBrownstein), Ph.D., is a postdoctoral researcher at Jean Monnet University (Saint Etienne, France). He completed his Ph.D. at Northumbria University (Newcastle, U.K.), where he assessed recovery of neuromuscular function following high-intensity intermittent exercise. His current research focuses on the acute integrative response to whole-body exercise in athletes, healthy active populations and clinical populations, with a focus on neuromuscular perturbations.

Guillaume Millet (@kinesiologui), Ph.D., is a professor of exercise physiology at Jean Monnet University (Saint-Etienne, France). After graduating from the University of Franche-Comté in 1997, he held various positions in Dijon, Saint-Etienne and Grenoble. Between 2013 and 2018, he was professor in the Human Performance Laboratory and the Faculty of Kinesiology at the University of Calgary (Canada) where he led a research group on neuromuscular fatigue. In 2019, he was named a senior member at the Institut Universitaire de France. His general research area investigates the physiological, neurophysiological and biomechanical factors associated with fatigue, both in extreme exercise (ultra-endurance) and patients (neuromuscular diseases, cancer, multiple sclerosis, ICU).

Viewpoints presented in SMB commentaries reflect opinions of the authors and do not necessarily represent ACSM positions or policies. Active Voice authors who have received financial or other considerations from a commercial entity associated with their topic must disclose such relationships at the time they accept an invitation to write for SMB.

Natural killer (NK) cells, which are found in the blood, are crucial in the prevention and treatment of cancer. They function by eliminating malignant tumors in an innate immune manner. NK cells express an array of activating and inhibitory receptors that recognize cancer cells without the need for immunization. Cytotoxicity is a process that results in damaging or destroying cells. The antitumor cytotoxicity of NK cells depends on their ability to recognize cancer cells and produce cytotoxic proteins. Mitochondrial bioenergetics is essential for optimizing NK cell effector functions, including increased cytotoxic potential and cytokine production.

Regular exercise reduces mortality associated with most cancers. An acute bout of exercise mobilizes NK cells that enter the bloodstream from peripheral tissues; it can modulate the antitumor cytotoxicity of NK cells by altering cellular protein contents in an intensity-dependent manner. However, patients with malignancies experience gradual declines in muscle strength and cardiorespiratory fitness, which can influence their ability to exercise. This may lead to a more sedentary lifestyle. High-intensity interval training (HIIT) has been shown to be a more effective modality for improving cardiorespiratory fitness than moderate-intensity continuous training in both healthy individuals and patients with cardiovascular disease.

Our study, published in the May issue of Medicine & Science in Sport & Exercise_®, involved 60 sedentary males who were randomly assigned to engage in either HIIT or moderate-intensity continuous training, or were assigned to a control group that did not receive exercise intervention. We observed that HIIT was superior to moderate-intensity training for enhancing exercise performance by increasing peak pulmonary ventilation and work-rate. Notably, both types of exercise training improved two cytotoxic characteristics of NK cells that involved the increases in cytotoxic proteins expressions and proliferative capacity of NK cells in the blood. Moreover, the two exercise regimens effectively elevated membrane potential and depressed cell matrix oxidant burden in the mitochondria of NK cells. This was associated with an increased oxygen uptake efficiency in NK cells.

NK cells are also important antiviral white blood cells that can rapidly respond to pathogens before an adaptive immune response occurs. Clinical studies in patients with COVID-19 have shown decreased NK numbers and function, resulting in decreased clearance of infected cells and increased tissue inflammation. Our previous and present studies indicate that moderate-intensity exercise training downregulated the senescent and inhibitory receptors on NK cells, thereby increasing clonal expansion and simultaneously improving NK cells’ ability to recognize and take cytotoxic action against viruses and cancer cells.

Our experimental findings could help determine effective exercise regimens for simultaneously improving cardiorespiratory fitness and the bioenergetic efficiency of NK cells in people living a sedentary lifestyle.

Jong-Shyan Wang, Ph.D., is a professor at the Graduate Institute of Rehabilitation Science at Chang Gung University, Taiwan. Dr. Wang was included in Stanford University Names World’s Top 2% of Scientists in 2021. His research focuses on developing exercise prescriptions for inflammatory/immunity, thrombotic and cardiovascular disorders.

Disclosure: This work was supported by the National Science Council of Taiwan and the Chang Gung Medical Research Program.

Viewpoints presented in SMB commentaries reflect opinions of the authors and do not necessarily represent ACSM positions or policies. Active Voice authors who have received financial or other considerations from a commercial entity associated with their topic must disclose such relationships at the time they accept an invitation to write for SMB.