Intense physical activity

The protons are removed so effectively by these two processes that, even during intense physical activity, the blood pH is maintained at or very close to normal (pH 7.4). 

Low energy intake with prolonged and intense physical activity... 

Ehn, L., Carlmark, B. HSglund, S. (1980) Iron status in athletes involved in intense physical activity. Med. Sci. 

Lactic acid, C2H4(OF[)COOH, is found in sour milk. It is also formed in muscles during intense physical activity and is responsible for the pain felt during strenuous exercise. It is a weak monoprotic acid and therefore a weak electrolyte. The freezing point of a 0.0100 m aqueous solution of lactic acid is —0.0206°C. Calculate (a) the / value and (b) the percent ionization in the solution. 

Some examples of physical activities commonly engaged in and the average amount of food Calories a 154-pound individual wiU expend by engaging in each activity for 1 hour. The expenditure value encompasses both resting metabolic rate food Calories and activity expenditure. Some of the activities can constitute either moderate- or vigorous-intensity physical activity depending on the rate at ... 

To reduce the risk of chronic disease in adulthood, engage in at least 30 minutes of moderate-intensity physical activity, above usual activity at work or home, on most days of the week. 

Lactic acid, C2H4(OH)COOH, is found in sour milk. It is also formed in muscles during intense physical activity and is responsible for the pain felt during strenuous exercise. 

Leon AS. Contribution of regular moderate-intensity physical activity. In Leon AS, ed. Physical Activity and Cardiovascular Health A National Consensus. Champaign, 111 Human Kinetics 1997 55-66. 

Intense physical activity requires rapid generation of ATP, usually for a relatively short time. Under these conditions substrates and oxygen cannot enter the muscle at an adequate rate to meet the demand, and muscle depends on anaerobic glycolysis of its glycogen reserves. As discussed in section 5.4.1.2, this leads to the release of lactate into the bloodstream, which is used as a substrate for gluconeogenesis in the liver after the exercise has finished. 

Less intense physical activity is often referred to as aerobic exercise, because it involves mainly red muscle fibres (and type IIA white fibres) and there is less accumulation of lactate. 

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