What kind of exercise is any form of exercise that demands more oxygen than the body can supply?

Giving an Aerobic Exercise Prescription

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Exercise capacity or endurance is increased by performing regular aerobic exercise at least three times per week. For primary prevention, although a fourth episode further increases exercise capacity, after the fourth episode per week, the incremental benefit is less. The greatest benefit of additional episodes of exercise per week is to assist with weight loss. For secondary prevention, there continues to be improvement in exercise capacity with additional episodes per week. Consequently, most cardiac rehabilitation programs recommend exercising most days of the week for an hour a day.

For primary prevention, aerobic exercise can be performed 3 days in a row to maintain fitness; however, the risk of an injury increases without adequate rest between episodes. It is therefore recommended that individuals exercise, at an aerobic level, every other day. Participating in a less intense walking program on intervening days may also assist with weight loss.

Aerobic exercise involves raising the heart rate to a specified point (60% to 80% of MHR) and maintaining that level of exercise for 30 to 45 minutes per session. Three 10-minute episodes in the same day accomplish the same effect as one 30-minute episode.

After ET, a safe aerobic training range is at a heart rate of 60% to 80% of MHR. This range is called thetarget heart rate. A PES of 5 to 7 can also be used in most patients; however, some patients have a poor perception of level of exertion, and therefore PES cannot be used.

Patients should avoid dehydration and weather extremes. Unlike what was done if the ET was performed for diagnostic purposes, they should warm up and cool down after each episode, especially older patients.

A repeat ET can evaluate the improvement after implementation of an aerobic exercise program. After introduction of an exercise program, it takes approximately 12 weeks of regular exercise to achieve a new level of exercise capacity.

To avoid boredom, it is recommended that an exercise prescription include more than one kind of aerobic exercise (e.g., swimming, biking, race walking, jogging, and aerobic dance).

An exercise prescription should include a target heart range or level of PES, duration of exercise sessions, frequency of sessions, and types of exercises that can be used to achieve the goals of cardiovascular conditioning (aerobic). For new exercise prescriptions, the rate of progression needs to be explained.

Competitive athletes want to use their training program to raise their anaerobic threshold (i.e., level of exercise at which they can no longer oxygenate all tissues). Anaerobic thresholds are now best measured with ventilator-expired gas analysis ET.

Aerobic Exercise Capacity

Numerous studies have demonstrated that cardiorespiratory fitness (oxygen consumption [VO2] max per kg weight at peak exercise) declines markedly with age. In cross-sectional studies, the decline is approximately 50% from the third to ninth decade. In longitudinal studies, a more pronounced age-associated VO2max decline is evident, regardless of habitual physical activity levels (Fig. 88.3).13 The decline is only partially explained by changes in maximal heart rate and other CV parameters. Sarcopenia, the age-related atrophy and weakening of skeletal muscle, contributes significantly to the age-associated decrease in VO2max. Age-related sarcopenia involves a reduced number, size, and function of muscle fibers. By age 75 years, muscle mass typically represents approximately 15% of body weight compared with 30% in young adults. Fast-twitch fibers atrophy to a greater extent than slow-twitch fibers, which likely contributes to decrements in strength that are proportionally greater than the loss of muscle mass. Increased intramuscular fat and decreased mitochondrial bioenergetics contribute to reduced muscle function.16 Effects of CVD (most notably HF) on skeletal muscle compound the effects of sarcopenia.17

The accelerated decline of aerobic capacity with age has important implications regarding functional independence and quality of life (QOL). Because many of the activities of daily living require fixed aerobic expenditures, they require a significantly larger percent of VO2max in older than younger adults. When the energy required for an activity approaches or exceeds the aerobic capacity of an elderly individual, he or she will be less likely to perform it.

Important Terms Defined

Aerobic exercise: Physical activity that does not require more oxygen than that which can be taken in by the body. Some examples of aerobic exercise include running, walking, jogging, and swimming. See also Anaerobic exercise.

Anaerobic exercise: Physical activity that requires the body to go all out, during which the muscles rely heavily on production of energy without adequate oxygen supply. Some examples of these activities include sprinting and lifting weights. See also Aerobic exercise.

Exercise: A planned, structured, and repetitive bodily movement done to improve or maintain one or more components of physical fitness. Areas of physical fitness include cardiorespiratory (such as heart and lung functions), muscular (such as power), metabolic (such as glucose tolerance), morphological (such as body composition), and motor (such as agility).

Recommended Amounts of Aerobic Activity for Prevention

To obtain substantial health benefits from physical activity, adults should do at least 150 minutes/week of moderate-intensity aerobic activity or 75 minutes/week of vigorous-intensity activity. Adults can do a combination of both moderate- and vigorous-intensity activity, using the rule of thumb that one vigorous-intensity minute of activity counts the same as two moderate-intensity minutes.9 Although previous recommendations were for bouts of aerobic activity of at least 10 minutes, bouts less than 10 minutes also appear to provide health benefits.

7.09.5.3.4.1 Aerobics

Aerobic exercise can have beneficial effects in the rehabilitation of cognition in TBI patients as it is believed to support angiogenesis and neurogenesis, both of which are important for brain repair. Aerobic exercise not only enhances cardiorespiratory fitness, but is also beneficial for symptoms like fatigue, impaired cognition and mood disturbances. A supervised aerobic exercise-training program can improve overall mood and acute mood responses in chronic ambulatory TBI patients (Weinstein et al., 2017).

Exercise in TBI patients can ameliorate depressive symptoms, this may be also an indirect effect of improved sleep quality which is commonly affected in TBI (Weinstein et al., 2017).

Preclinical studies show improved learning and memory and upregulation of brain-derived neurotrophic factor in the hippocampus in brain injury after exercise. Exercise induces BDNF expression in the hippocampus via peripheral exercise factors, such as lactate and beta-hydroxybutyrate (Stephan and Sleiman, 2019). In a pre-post intervention study, a vigorous aerobic exercise regime undergone for 12 weeks in chronic TBI patients significantly improved cognition. Besides overall cognitive function, specific gains were seen in the domains of processing speed and executive functioning. Moreover, the magnitude of these cognitive gains strongly related to improved cardiorespiratory fitness, supporting the role of aerobic exercise in improving cognition (Chin et al., 2015).

Various mechanisms are thought to be responsible for these benefits of aerobic exercise, including psychological as well as physiological. Psychological factors could be increased self-esteem, self-efficacy, self-image, social interaction with research staff and distraction from worries, anxiety, and depressing thoughts. Physiological mediators have been suggested to improve neuroplasticity and neuroprotection via increased cerebral blood flow, neurogenesis and release of various chemicals such as, vascular endothelial growth factor, brain-derived neurotrophic factor, and serotonin. Additionally, exercise improves core body temperature, analgesia, and attenuation of stress responsiveness (Kreber and Griesbach, 2016; Weinstein et al., 2017). It is crucial to consider the appropriate timing, type and intensity of exercise when treating TBI patients; intense exercise in the acute-post injury phase may prove to be counterproductive by worsening cognition (Kreber and Griesbach, 2016).

Exercise

Regular aerobic exercise enhances caloric expenditure and is thought to have a synergistic effect on weight loss during a hypocaloric diet in obese individuals. In addition, exercise training provokes beneficial cardiovascular and autonomic adaptations, namely a reduction in blood pressure and sympathetic activity (whole-body and renal norepinephrine spillover rates), preservation of lean body mass and improvements in baroreflex function, insulin sensitivity and lipoprotein profile. Interestingly, randomized trials have failed to show additive benefits on sympathoinhibition (MSNA, whole-body norepinephrine spillover rate, venous norepinephrine) for a combined exercise-hypocaloric diet intervention versus hypocaloric diet alone. This suggests that weight loss is the prime mover in sympathetic neural adaptation during lifestyle intervention.

Aerobic exercise

The positive effects of aerobic exercise on circulatory and pulmonary systems are well known, and there may be similar benefits for cognition and brain in older adults. Research by Colcombe, Kramer, and others suggest that executive functions and associated brain regions may benefit from higher levels of aerobic exercise. Thus, the effects of aerobic exercise may be regional, rather than global, particularly targeting neural regions, most vulnerable and also most malleable. Experimental and observational studies on the benefit of aerobic exercise in old age support the notion of continued plasticity even in late life.

Exercise

Systematic reviews have shown aerobic exercise to improve pain and other fibromyalgia symptoms. The beneficial effects of exercise likely involve activation of endogenous analgesic systems, and an increase in well-being and control (Williams and Clauw, 2009). Strength and flexibility programs require further study to determine effectiveness (Busch et al., 2008).

Many fibromyalgia patients are deconditioned. A successful exercise program relies on starting according to the patient’s abilities, and progressing slowly as tolerated (Busch et al., 2008; Russell, 2008; Goldenberg, 2008; Williams and Clauw, 2009). Water-based exercise is often better tolerated and may work best initially (Abeles et al., 2008).

3.2.1 Cardiovascular fitness theory

The beneficial effects of aerobic exercise are well established by improving cardiac output, oxygen consumption, stroke volume, muscle metabolism, and elasticity of the blood vessels (Lovallo, 2005). However, high-intensity or vigorous exercise might discourage the elderly people from taking part in doing exercise regularly (Berger & Owen, 1988; Lan, Chou, Chen, Lai, & Wong, 2004). Alternatively, a moderate level of exercise regimen has been suggested to improve cardiovascular functions in the long run (Hsu et al., 2016; Stanton & Arroll, 1996). In addition, moderate exercise has been shown to have therapeutic effects on depression (Fadillioğlu, Kaya, Uz, Emre, & Ünal, 2000) or even bring a comparable mood elevation as observed with athletes during vigorous exercise (Berger & Owen, 1992). It has been proposed that health Qigong practice, a form of moderate demanding activity, can stabilize the sympathovagal function (Lee, Kim, & Lee, 2005) and make influence on the autonomic nervous system (ANS) (Payne, Fiering, Leiter, Zava, & Crane-Godreau, 2017). Therefore, it is unnecessary to attain cardiovascular fitness and mood elevation through aerobic exercise only. The breathing techniques and movements of health Qigong can also help regulate ANS activity and ultimately enhance cardiovascular fitness.

The “breath regulation” (tiao xi) in Qigong requires individuals to practice long, deep and smooth diaphragmatic breathing. Such deep breathing with short period holding make the individual to concentrate at the dantian (center of abdomen). Researchers suggest that such rhythmical and diaphragmatic breathing possibly serves as an autonomic or endocrine training that improves cardiac output, ventilatory efficiency, oxygen consumption, carbon dioxide production, mood stabilization, and flexibility of ANS, consequently achieving a homeostatic state (Lan et al., 2004; Lee, Lee, Kim, & Moon, 2003; Lim, Boone, Flarity, & Thompson, 1993). Specific physical movements in health Qigong involve stretching, massaging, twisting, and even a pressuring on the spine, internal organs, and muscle groups, which can further enhance blood circulation and physical functions (Zeng, 2004).

Like biofeedback, Qigong helps the practitioner develop psychophysiological self-regulation skills that help improve one's awareness of bodily functions such as blood pressure and respiratory rates that are conventionally considered only involuntary (Lehrer, 2003). Such self-regulation is believed to help the practitioner restore health (Cohen, 1997). A blissful psychologic state induces more positive emotions, which help enhance sympathovagal balancing, higher parasympathetic heart modulation, stabilization of the sympathetic nervous system, and cardiac autonomic tone (Lee et al., 2002; Lee, Choi, & Yook, 2005).