Exercise Physiology MCQs

In response to heat acclimatization (acclimation) there will be an increase in sweating. There is change in the internal sweat gland cells to increase their sweating capability. When a person is exposed to hot weather for 1 to 6 weeks, he or she begins to sweat more profusely, often increasing maximum sweat production to as much as 2 to 3 L/hr. Evaporation of this much sweat can remove heat from the body at a rate more than 10 times the normal basal rate of heat production. Also there will be decrease in the concentration of sodium chloride in the sweat, which allows progressively better conservation of body salt which is caused by increased secretion of aldosterone by the adrenocortical glands which results from a slight decrease in sodium chloride concentration in the extracellular fluid and plasma.

Ans. C. Acetylcholine receptors Examiner just wants to know the receptors which are present in sweat gland. Sweatingis under the control of sympathetic system. But the neurotransmitter is acetylcholine which acts on cholinergic sympathetic receptors.

Lean body mass means fat free mass BMR depends on lean body mass Reference: Ganong, 25 th edition page no.488

Both isotonic and isometric are strengthening exercises Since isometric exercises increases both systolic and diastolic BP, it is always the isotonic exercises which are preferred ones. Reference: Guyton, 13th edition page no.1086

Nonshivering thermogenesis refers to increase in metabolic rate that is not a result of muscle activity. It appears to be elicited through sympathetic stimulation and circulating catecholamines. Epinephrine and norepinephrine which are released increases metabolic activity and heat generation. Ref: Guyton and Hall - Textbook of Medical Physiology, 10th Edition, Pages 821, 828-829; Medical Physiology: Principles for Clinical Medicine By Rodney A. Rhoades, 4th Edition, Page 568; Fundamentals of Human Physiology By Lauralee Sherwood, Page

Obesity occurs because of decreased BMR, increased food intake, and reduced activity Reference: Ganong, 25 th edition page no.488

During exercise, minute ventilation and alveolar ventilation increase linearly with carbon dioxide production up to a level of about 60% of the maximal workload. Above that level, called the anaerobic threshold, muscle lactate spills into the circulation causing a metabolic acidosis, characterized by a decrease in pH and [HCO3-]. The increased [H+] stimulates the peripheral (not central) chemoreceptors to increase alveolar ventilation, resulting in a decrease in PaCO2. Reference: Ganong, pp 681-683. Levitzky, pp 208-212.

During exercise, coronary blood flow increases by more than four times than normal Cerebral blood flow remains largely unchanged Reference: Guyton, 13th edition page no.1093