Introduction
Exercise is included in both clinical and regulatory literature as an established intervention which can modify risk factors across various health domains. Exercise, in comparison to incidental physical activity, is identifiable as a structured and repetitive movement done with a purpose towards achieving reasonable outcomes for cardiovascular capacity, muscular strength, and metabolic function.
Global data from WHO and CDC identify physical inactivity as a significant contributor to the increase in non-communicable diseases, such as type 2 diabetes, ischemic heart disease, and certain cancers. This article reviews the benefits of exercise, in terms of mechanisms, to specific diseases to compatibility in guidelines perspectives.
Immediate & Short-Term Benefits
Mood and Stress Indicators
Exercise causes an immediate neurochemical reaction (endorphins, serotonin, and elevated BDNF). This response contributes to decreased anxiety measured in randomized clinical trials and mood stabilization. Moderate intensity exercise has also been associated with a measurable reduction in cortisol via an HPA axis response.
Energy & Reduction of Fatigue
Better oxygen uptake, greater ATP production in the mitochondria, and improved cardiovascular function, lead to greater feelings of energy. Fatigue scores are reduced in intervention studies after a single 30-minute session of aerobic activity. This supports exercise, high of course, as a rapid intervention to reduce fatigue.
Sleep Quality
Polysomnography shows decreased sleep onset, stall sleep latencies and increased slow-wave sleep after weekly exercise exposure. Timing of exercise is more complicated; morning or afternoon exercise helps to set environmental cues that support circadian rhythm, however, exercise in the late evenings can disrupt initiation of sleep.
Cognitive Performance
An elevated cerebral perfusion during and soon after exercise ushers better working memory, executive function and attentional control. These increases in cognitive ability have implications for work, especially when jobs require greater levels of exertion.
Physical Health Benefits – Medium and Long Term
Cardiovascular and Metabolic Regulation
Exercise is associated with lower systolic and diastolic blood pressure, improved lipid panels, and enhanced insulin receptor sensitivity. Prospective cohort studies have found a 20-35% decrease in cardiovascular mortality for those engaged in a physical activity effort.
Weight Management or Control and Body Composition
Calorie energy expenditure from engaged structured exercises can be used in a weight loss program. Resistance training preserves lean mass during caloric restriction. Longitudinal studies have shown a reduced risk of weight regain in individuals who engage in both aerobic activity and resistance training.
Musculoskeletal and Skeletal Adaptations
Mechanical loading directly promotes osteoblastic activity of bones, which translates into favorable increases in total bone mineral density, as well as a favorable reduction in fracture risk. Resistance exercise also helps reduce and prevent sarcopenia in older individuals, enabling a retaining of muscle function and mobility when advanced age sacrifices such attributes.
Lower Risk of Cancer and Chronic Disease
Exercise decreases chronic inflammation and improves immune monitoring which is both important to the carcinogenesis process. Observational studies suggest the less risk of developing breast, colorectal, and endometrial cancers the more physical activity is performed.
Longevity and Mortalities
There have been several recently reported dose-response meta-analyses which confirm that individuals with a higher level of activity that meet WHO guidelines experience improved life expectancy and lower mortality. Even minor increases in activity are beneficial for overall survival rates.
Mental and Cognitive Health Lasting Effects
Depression and Anxiety Effects
Exercise generates similar effects as pharmacotherapy for individuals with mild to moderate depression. Psychosocial adaptation takes place due to it promoting neurogenesis and the release of neurotransmitters in exercise along with a decrease in inflammatory markers.
Cognitive Aging and Dementia Prevention
Cohort studies show propelling physical activity relates to a lower incidence of Alzheimer’s disease or vascular dementia. These mechanisms may occur by the ways of neurogenesis in the hippocampus and improved regulation of cerebral blood flow.
Psychosocial Functioning
In addition to pharmacological factors, exercise is associated with improvements to self-efficacy, increased confidence, and social connection. Group-based exercise is beneficial to contribute to resilience because it provides ordered social connections.
Advantages Over Life Stages and Population Groups
Children & Adolescents
Physical activity promotes bone growth, effective biomechanical coordination, and enhances academic performance. Neurologically, children and adolescents derive greater attention span and cognitive problem solving.
Adults
For middle-aged adult populations, physical activity lowers risk for hypertension, spares metabolic flexibility, and staves off early degenerative conditions in the musculoskeletal system.
Older Adults
Physical activity is an intervention to counter the effects of age related sarcopenia, improves balance, and lowers the risk of falls. Research has demonstrated improved executive function and a slower rate of cognitive decline in older adults who participated in exercise, physical activity or regular movement.
Chronic Disease Patients
- Diabetes: Exercise has improved HbA1c levels and enhanced use of insulin in patients.
- Cardiovascular disease: Structured aerobic exercise is a component of cardiac rehabilitation programs that reduce likelihood of another cardiovascular incident.
- Arthritis: Engaging in low-impact physical activity eases severity of overall arthritis pain, and preserves range of motion in joints.
- Cancer Survivors: Exercise contributes to recovery from cancer treatment reducing fatigue levels and risk of recurrence.
Pregnancy & Postpartum
In supervised settings, engaging in physical activity reduces risk of gestational diabetes, preeclampsia, and excessive weight gain. Postpartum engagement in physical activity restores integrity of the musculoskeletal system and improves psychological well-being.
Athlete & Occupation Based Performance
Professional athletes develop and improve performance following an exercise program, and special populations (ie, military) demonstrate lower rate of injury and improved performance on job specific tasks when conditioning improves.
Mechanisms and Biological Basis of Benefits
- Metabolic Changes: Enhanced mitochondrial density, improved insulin signaling cascades, and regulation of adipokine secretion.
- Cardiac Changes: Endothelial nitric oxide synthase activation enhances vasodilation and angiogenesis.
- Musculoskeletal Modifications: Hypertrophy due to satellite cell activation and osteoblastic remodeling in response to mechanical strain.
- Neuroplasticity: Enhancing synapse integrity, neurogenesis within the hippocampus, and neurotransmitter turnover.
- Inflammatory modulating effects: Decreased levels of TNF-α and CRP immune indicators, and increased levels of anti-inflammatory cytokines including IL-10.
Policy, regulation, and guideline structures
Policy, regulation, and guideline structures: Public health authorities including WHO, CDC, and European Society of Cardiology advise the minimum level of activity for public health population outcomes As a way of expressing their minimum activity threshold in their guidelines and recommendations, 150 minutes of moderate or 75 minutes of vigorous of aerobic activity per week with strength for twice a week are recommended.
From a regulatory perspective claims relating to benefits of exercise in government communication about health are seen as equivalent to dietary supplement claims required under 21 CFR 101, where statements about disease need to be validated. In public campaigns exercise is referred to without using disease reduction language to be compliant with the regulatory framework.
Risks, Contraindications, and Barriers
Barriers
Limited time, environmental factors, and motivation are still the leading barriers. Scheduling the exercise as part of a framework and institutional support can address and mitigate these barriers.
Risks and Injuries
In an unregulated environment high training volumes are known to lead to overuse injuries, stress fractures, and hormonal dysregulation. Preventative methods to monitor volume are warming up properly, resting, and professional monitoring.
Contraindications
Patients with unstable angina, a progressive injury related to the musculoskeletal system, and uncontrolled hypertension must be cleared prior to beginning exercise protocols.
Behavioral Science of Adherence
Adherence to exercise is facilitated by evidence-based methods:
- Goal Setting: Create SMART goals which provide measurable milestones.
- Monitoring: Use digital trackers as a measure of feedback and progress.
- Habit Formation: The more repeated practice, the more consistent the behavior will be.
- Motivational Interviewing: This can be clinically applied or in the fitness environment to help maintain compliance.
- Social Reinforcement: Involvement in groups creates more accountability for compliance and volume for returning.
Evidence Rating and Claims Verification
Exercise science is based on observational studies, meta-analyses, and randomized-controlled trials. The GRADE framework assigns levels of confidence for the quality of evidence, with strong recommendations requiring multiple RCTs of high quality.
Observational evidence provides support of association, but these must be made cautiously. This rigor in methodology reflects the verification of evidence provided by the regulated industry when providing data to support an efficacy claim that could be reproducible.
Recommendations for practice and policy
- Promotion of exercise as part of a non-pharmacological intervention using a structured exercise prescription in clinical settings.
- Increase opportunities for behaviors to reduce sedentary time in the workplace.
- Include a recommendation for exercise in physical activity and nutrition guidelines with a primary focus in the field nationally.
- Further promote longitudinal studies that have implications for improved dose-response relationships with longitudinal studies to promote population-specific adaptations to exercise programs, and general implications for practice.
FAQs
What is the difference between structured exercise and general activity?
Exercise is a purposeful and repeated behavior, while general activity can happen on its own. Structured exercise offers better evidence for disease prevention.
How quickly do you see benefits?
Change in mood and energy happens in hours, while cardiometabolic changes happen over weeks during regular exercise.
Will exercise alone prevent chronic disease?
Exercise is very protective, but it is best with diet, sleep, and clinical advice.
Is one type of exercise better than another?
Aerobic and resistance exercises will confer some benefits that are separate from each other, and a combination is best.
How much is too much?
Exercise and training beyond the capacity to recover from a training session will result in ‘overtraining syndrome’ and create a greater risk for injury.
What adjustments are warranted for vulnerable populations?
Older adults, pregnant women, and people with chronic disease may need to adjust to a lower intensity and should have medically supervised exercise testing prior to exercise initiation.
What is a method for maintaining adherence for the long-run?
Adherence strategies are real structured goal-setting with monitoring, and some kind of group process.