prof k. sivapalan department of physiology, faculty of medicine, university of jaffna

BENEFITS AND PROBLEMS OF EXERCISE

Prof K. Sivapalan

Department of Physiology,

Faculty of Medicine,

University of Jaffna

Introduction

• Evolution: hunter-gatherer

• Body Composition: Muscles (40%)and Bones

• Motor Centers in Brain: Cerebellum and Basal ganglia, Motor Cortex, Brain Stem and Spinal Cord

• Control of physical activity: Neocortex [on the basis of short and long term health, physical and other benefits] vs Limbic System [on the basis of emotion]

• Technology: Automation and communication → comfort → unhealthy life style

• Tissues: “USE IT OR LOSE IT”

09.11.2012 Benefits and problems of Exercise 2

Exercise


Nutrition

• Energy intake = exercise energy expenditure + energy needed for all other functions ± body energy content

• Inadequate energy intake: ↓ muscle mass; ↓bone density; ↑risk of fatigue, injury, and illness and reproductive dysfunction.

• Eating: exercise before or after - after for glycaemic control.

• Vitamins and minerals: Vitamins B, C, D, E and beta carotene and minerals like calcium, iron, zinc, magnesium and selenium – ?weight reduction and diet restriction.

• Fluid & electrolytes: dehydration and hyponatremia (muscle cramps)


Metabolism

• Enzymes for oxidation of Fat- ↑, Carbohydrate- ↓

• ↑ oxidative capacity, ↓ glycogen depletion

• ↑ insulin sensitivity and ↓ leptin level

• When Energy Intake >Energy Expenditure, ↑ serum cholesterol and phospholipids.

• Sprint- ↑post-exercise metabolism –weight reduction.


Exercise and Diabetes

• Regular exercise reduces the risk of type 2 diabetes in overweight/obese individuals.

• Regular walking exercise: increased energy consumption, and decreased FBG, HbA1c, and TG levels. Better response if done after dinner.

• Incidence of complications of type II diabetes might be reduced by implementing a regular walking exercise program.

• Moderate exercise: muscular uptake of glucose exceeds hepatic glucose production, and blood glucose decline during the activity.

• Plasma insulin levels concomitantly fall, making the risk of exercise-induced hypoglycemia low as long as the individual is not injecting insulin or taking insulin secretagogues.


Skeletal Muscle


Skeletal Muscles

• Hypertrophy

• Feed arteries in rats: young- increase in number of vessels, old- increased cross sectional area of the vessels

• Gene expression: heat shock proteins- maintain homeostasis, facilitate repair from injury and preserve muscle function in aging.

• Anabolic effect of nutrient intake- prevent sarcopenia in old age.


Bones, Tendons and Ligaments


Muscle

Tendon

Articular Cartilage

Epiphyseal cartilage

Bone

Joint Capsule - Fascia

Bones, Tendons and Ligaments

• Articular cartilage volume: proportional to physical activity – exercise in older women did not show increase.

• Postmortom findings in Horse: increase in hyaline cartilage, calcified cartilage and subchondral bone thickness- ? Growing children.

• Joint form: development after birth is modified primarily through differential rates of articular cartilage proliferation across articular surfaces. ? By the magnitude and orientation of stresses in the articular cartilage.

• Epiphysial growth is stimulated by weight bearing.

• Bone mass and architecture: Load-bearing is an important functional influence. Bone's adaptive response to load-bearing depends on functional strains. Remodeling – along the line of stress.


Injuries

• Excessive weight bearing on epiphysis - damage and stunting.

• Injuries to muscles and bones occur by over use, accidents and foul play in games.

• More physically active individuals had more knee abnormalities.

• ? Running and osteoarthritis- may depend on pre-existing health of the joint.

• Stress of competitive sports overweigh the benefits of exercise by the action of stress hormones.

• Effects of exercise in illnesses like viral infections, liver diseases and kidney diseases need consideration.


Immunity• Antibody production: optimal in moderate exercise, suppression in

intense exercise.

• This transient suppression returns to normal in 24 hours. ? Can become a chronic depression of acquired immunityif intense exercise continues- may be due to elevated circulating stress hormones, alterations in the pro/anti-inflammatory cytokine balance

• Exercise alters the number and function of neutrophils, monocytes and natural killer cells- ?anti inflammatory effect of exercise.

• Prophylactic effect on insulin resistance, atherosclerosis, tumour growth and neurodegeneration. ? Antiinflammatory effect

• Enhanced anti-tumour immunity: ?protection against postmenopausal breast cancer and cancers of colon, endometrium, lung and pancreas.

• AIDS: Moderate physical activity may slow HIV disease progression.


Respiratory System

• Improved pulmonary function at rest and exercise [greator operating lung volumes]

• ?increased incidence of respiratory infection- ?immuno-suppression by exercise. ? Cool air and dust load of hyperventilation.? Body temperature fluctuations- exercise and bathing.

• Exercise induced asthma- ?triggered by cool air

• Significant benefits from exercise training in Acute Exacerbation of Chronic Obstructive Pulmonary Disease, COPD, and conditions that are common co-morbidities


Blood• Thrombotic risk increases with aging-↑fibrinogen, factor VII, PAI-1

and plasma viscosity. Regular physical exercise ↓ risk

• Acute exercise [unaccustomed strenuous physical exertion]: transient activation of the coagulation system, accompanied by an increase in the fibrinolytic capacity.

• Acute exertion may precipitate ischeamic cardiac problems due to:

– Increased coagulability

– ?reduced plasma volume and haemo-concentration

– Rupture of a small, inflamed, coronary plaque and the activation of thrombogenic factors

• Long-term moderate or strenuous physical activity is associated with a considerable reduction in cardiovascular morbidity and mortality.


Cardiovascular System

• Resting heart rate, heart rate recovery, exercise HR, and exercise blood pressure: strong association in runners and swimmers, less in walkers and least in sedentary.

• Larger end diastolic volume and wall thickness, more in males [not exceeded the limit of resolution].

• Transport capacity: ↑blood flow and capillary exchange. Structural- cross-sectional area and angiogenesis- vascular remodelling. Functional- control of vascular resistance.

• Improve endothelial function, vascular smooth muscle function, antioxident systems, heat shock proteins, ↓inflammation.

• While strenuous exercise increases oxidative metabolism and produces a pro-oxidant environment, regular moderate physical activity promotes an antioxidant state and preserves endothelial function.


Cardiovascular Rehabilitation

• Lowering BP: A bout of afternoon exercise interrupted with short rest periods is recommended

• After Coronary Bypass: improved exercise capacity associated with restorations of peripheral oxygen utilization in both patients with and without Diabetes.

• Congestive Heart Failure: Aquatic exercise improves exercise capacity and muscle function in patients with the combination of CHF and DM

• Intermittent Claudication: no improvement observed in experiment on old women.

• Exercise training: effective antioxidant and anti-atherogenic therapy

• Adverse events observed:12.2% for SBP, 10.4% for TG, and 13.3% for HDL-C. About 7% of participants experienced adverse responses in two or more risk factors.


Higher Functions of the Brain

• Early life stress- maternal separation- ?reversed by exercise in rats.

• Reduction of depression and fear of falling in older persons by physical training

• Exercise training resulted in significant improvements in depressive symptoms, fatigue and aspects of quality of life

• Exercise with integrated cognitive and motor coordination, may help with preservation of global ability in elders at risk of cognitive decline – observed in Chinese old subjects

• Other suggested benefits- improved problem solving ability and feeling of wellbeing


Sleep• Exercise 5-6 hours before sleep time enhances sleep

-In animals- exercise increases NREM sleep.

• Six months of training improved sleep in elderly.

• Participation in an exercise training program had moderately positive effects on sleep quality in middle-aged and old.

• Moderate treatment efficacy for the reduction of apnea-hypopnea index [AHI] in sedentary overweight/obese adults: Exercise seems to improve the mobility, fatigue, and sleep quality in Stage IV lung and colorectal cancer patients.

• Physical exercise could be an alternative or complementary approach to existing therapies for sleep problems.


Reproductive System• Working Capacity (at HR170) is decreased in luteal and menstrual

phases

• Strenuous exercise: delayed puberty, luteal phase deficiency, oligo-amenorrhea or anovulation – disturbance of GnRH pulsatility due to ? inadequate energy intake.

• Hypoestrogenemia: premature osteoporosis. Most cases are reversible with dietary and exercise modifications.

• Safe limits of exercise in pregnancy depend on previous exercise habits.

• Pre-eclampsia: improved blood flow, reduced blood pressure, enhanced placental growth and vascularity, increased activity of antioxidant enzymes, reduced oxidative stress and restored vascular endothelial dysfunction.

• Menopausal symptoms- [night sweats, mood swings, and irritability] reduced by aerobic training.

• High impact sports activities may produce urinary incontinence09.11.2012 Benefits and problems of Exercise 19

Sexuality• Sexuality enhancement in male subjects was proportional to fitness.

(frequency of various intimate activities, reliability of adequate functioning during sex, percentage of satisfying orgasms, etc)

• ↓Sexual activity following cardiac events: fear of coital death or re-infarction, dyspnea, anxiety, angina pectoris, exhaustion, depression, loss of libido, impotence, partners anxiety or concern, and feeling of guilt.

• Patient that can climb one or two flights of stairs can keep his marital sexual life without running further risk of cardiac symptoms

• ?Risk of Myocardial Infarction during sexual activity is three times higher [Sex act as acute exercise]

• Regular exercising- protective effect, improved sexual activity

• Erectile dysfunction is often improved by physical activity.

• Adolescents indulge in sexual activities due to lack of recreation


Rehabilitation - Cancer

• Prostate cancer: positive benefits for improving surgical outcomes, reducing symptom experience, managing side effects of radiation and chemotherapy, improving psychological health, maintaining physical function, and reducing fat gain and muscle and bone loss.

• Increase survivorship by 50%-60% in breast and colorectal cancers.

• In the wide range of cancer populations, both young and old, and with curative and palliative intent, exercise is well tolerated and benefits the patient psychologically and physically.


Rehabilitation- old age

• The proportion of the aged population is increasing and minor illness will render them dependent

• Exercise training was feasible and effective in reducing fear of falling and improving dynamic balance and isometric strength in institutionalized older people with fear of falling.

• Older women can effectively change the decline in physical ability associated with aging by exercising.

• The 60-65 year group was capable of converting physical activity into health benefits in both the short and long term.


Conclusion • There is much evidence that a moderate amount of exercise is

needed for the maintenance of functional integrity of all body systems.

• It is important for growth and development of children

• Exercise can readily produce a 10 to 20% improvement in strength and aerobic power, effectively postponing functionally important thresholds for some 10 to 20 years.

• In the west, regular exercise is rapidly gaining widespread advocacy as a preventative measure in schools, medical circles and in the popular media

• In a Medical Faculty in India, of those who were currently exercising(50%), the proportion of boys was (62%) more compared to girls (38%). Lack of time, laziness, and exhaustion from academic activities were identified as important factors for not doing exercise.


WHO Recommendations (more exercise- more health benefits)

• 5–17 years:

– at least 60 minutes of moderate to vigorous-intensity physical activity daily.

• 8–64 years: [in bouts of minimum of10 minutes]

– at least150 minutes of moderate-intensity aerobic physical activity weekly, or

– At least 75 minutes of vigorous-intensity aerobic physical activity weekly, or

– an equivalent combination.

• > 64 years:

– as above depending on their abilities and conditions.



FOR HEALTHY LIFE…

Life long moderate exercise is a need

but stressful exercise can be

harmful

THANK YOU


prof k. sivapalan department of physiology, faculty of medicine, university of jaffna

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