++
LEARNING OUTCOMES
Define the general dose–response relationship and the link between physical activity and all-cause mortality.
Describe the relationship between energy expenditure and risk for chronic disease.
Identify the different categories of calorimetry, and describe the advantages, disadvantages, and validity of each method.
Demonstrate how to calculate oxygen consumption, carbon dioxide production, respiratory exchange ratio (RER), and energy expenditure from gas exchange data via the Haldane transformation.
Define oxygen deficit and excess post-exercise oxygen consumption (EPOC), including the primary factors that contribute to the magnitude of each parameter.
++
ANCILLARY LINK
Visit DavisPlus at http://davisplus.fadavis.com for study and practice resources, including online quizzes, animations that help explain physiological processes, podcasts concerning news and career trends in exercise physiology, and practice references.
++
VIGNETTE
Norman is a 52-year-old man who was recently told by his doctor that he needs to start exercising to avoid the many complications that often accompany obesity. He is 5’10” (178 cm), weighs 260 lb (118.2 kg), and has been mostly sedentary his entire adult life. He is hesitant about working with a personal trainer at this point, but asks the advice of one of the trainers at his local health club. The trainer tells him that the safest way to get started is with recumbent cycling, because it is a non–weight-bearing activity that is perfectly suited for beginning exercisers. Norman commits to using the recumbent cycle three times each week for 20 minutes per session and successfully maintains that amount of exercise for 2 months before again seeking out Najat, the trainer who helped him get started. He tells Najat that he has lost 10 lb and feels ready for a more structured approach to improving his fitness.
How can Najat individualize and progress Norman’s training regimen while maintaining high levels of both safety and effectiveness?
Najat begins by determining how many calories Norman has been burning each week and adjusts the duration of his workouts to reach an initial goal of 1,000 calories per week. She realizes, however, that Norman’s program will need to achieve 2,000 calories per week to promote continued weight loss, a goal consistent with his doctor’s overall recommendation.
After about 4 more months of exercising on the recumbent cycle, in addition to performing two full-body resistance training circuits each week, Norman is ready to add some variety to his workouts and start increasing his energy expenditure. Najat recommends that Norman now walk two or three nights each week after dinner to complement his current training program and add another weight-bearing activity, which is important for Norman’s overall health. Najat estimates that these activities collectively will now exceed 2,000 kcal/week, the target to effectively allow Norman to lose weight.
Norman is now 8 months into his exercise program, including 6 months of working with Najat. Both Norman and his physician have been thrilled with the results, as Norman’s weight has declined ...