Optimal Physical Health
Surgeon General has determined that lack of physical activity
is detrimental to your health and recommends moderate activity:
150 calories per day or 1000 calories per week. The American
College of Sports Medicine suggest all adults should engage in
30 minutes or more of moderately intense physical activity daily.
This level of activity corresponds to 200 kcals a day (Pate RR,
Pratt M, Blair SN, et al 1995). See Calorie
Other authorities suggest that the least amount of activity
for optimal physical health is about 1500-2000 kcals a week of
light and moderately intense activities. Additional physical
health benefits come with increased intensity and eventually
level off at around 3500 kcals per week (Peterson & Bryant
Children and adolescents are recommended to engage in at least
60 minutes of physical activity on most, and preferably all,
days of the week (USDA 2005). For ideal BMI, the minimum recommended
daily steps for 6-12 year old children are 12,000 steps/day for
girls and 15,000 steps/day for boys (Tudor Locke et al 2004).
See Step Distance
The ACSM recommends to target a weekly exercise expenditure
of approximately 1000 kcals a week (e.g. 3 sessions of 300 Calories
or 4 sessions of 200 Calories) (ACSM 1995). See Calorie
Review of the scientific literature suggests that moderately
intense aerobic activity needs to be performed most days of the
week to bring about significant fat loss. Some sources recommend
brisk walking progressing to 45 minutes or more daily. Other
authorities recommend working up to 60-90 minutes of daily physical
activity for weight loss.
The USDA recommends at least 60 to 90 minutes of daily moderately
intense physical activity while not exceeding caloric intake
requirements to sustain weight loss in adulthood. About 60 minutes
a day may be needed to prevent weight gain. (USDA 2005).
High Intensity Interval
Training (HIIT) has shown to be more effective in lowering
body fat than traditional aerobic exercise. Begin such a program
only after a period of general conditioning for adequate adaptation
and greater participant adherence. However the combination of
aerobic and anaerobic exercise may utilize more fat than either
type of exercise alone, particularly since greater recovery is
required between sessions of anerobic activity. Also see Fat Loss.
Alternating weight bearing with non-weight bearing exercises
every other day may be recommended to minimize the repetitive
orthopedic stresses of exercising daily. See Overtraining.
cardiorespiratory fitness, ACSM (2000) recommends intensities
between 55% and 65% to 90% of maximum heart rate, or between
40% and 50% to 85% of oxygen uptake reserve (VO2R) or Heart Rate
Reserve (HHR). ACSM suggests low-fit or deconditioned individuals
may experience improvements at exercise intensities of only 40%
to 49% HRR or 55% to 64% Maximum Heart Rate (HRmax). Skinner
et. al. (2004) remarks, "Because 'quite unfit', sedentary
subjects are already doing enough activity in their daily lives
to maintain a VO2 ventilatory threshold at levels that are generally
greater than 50% VO2R, it is not necessary to reduce the prescribed
intensity to 40% VO2R, as recommended by the ACSM."
Cardiovascular fitness improvement is dependent upon the exercise
program (mode, frequency, duration, intensity of exercise) as
well as the individual participant (fitness level, age, and health
status). Also see Running Risk
/ Benefit Study. For the average person aerobic training
programs typically produce an increase of VO2 of 5% to 20% (Pollock
1973). Those with low initial levels of fitness and those exhibiting
large losses of body weight will exhibit up to a 40% improvement
of VO2 max. Similarly, only modest improvements may be expected
from individuals with high initial levels of fitness or those
who exhibit little change in body weight (ACSM 1995).
Intensity, duration, and frequency are somewhat inversely
proportional. If one component increases, the others may be decreased
to a degree. When a program has been established, intensity is
the least forgiving component for cardiovascular fitness. An
increase of duration or frequency cannot make up for a significant
decrease of intensity without a decrease of cardiovascular fitness.
Cardiovascular fitness can be expressed as maximum oxygen
uptake (VO2 max). This is the amount of oxygen the body can utilize
per unit weight per unit time [ml / (kg x min)]. Since measuring
oxygen consumption directly is not feasible, many methods of
measuring VO2 max have been developed. These cardiovascular tests
have been validated by measuring the direct correlation of VO2
max and estimate cardiovascular fitness. These results of a cardiovascular
fitness test can be used to prescribe an exercise program based
on the participant's fitness level. See Aerobic
The inclusion of resistance
training is important for a sound overall exercise program
but will not significantly increase VO2 max. Circuit
weight training (e.g. 10 to 15 repetitions with 15 to 30
seconds between weight stations) improves VO2 max an average
of about 5%. For this reason circuit training is not generally
recommended as an activity to improve cardiovascular fitness.
general, the best exercise for a specific sport is the sport
itself. Additional exercises should condition the particular
components of fitness
specific to the sport. The specific muscles involved, type of
muscular contraction, intensity, duration, recovery time, and
motor skill must be considered. Specific components of the sport
may need to be trained separately.
Short Sprint Interval Training
and Interval Training can
supplement traditional cardiovascular fitness Training (see Sports Conditioning Program). Periodization
may be implemented for continued progress and for specialization
of particular components. For periodization examples, see Marathon Training,
and weight training
periodization. Also see Training
American College of Sports Medicine (1995) Principles of
Exercise Prescription, William & Wilkins, 5.
American College of Sports Medicine (2000) ACSM's Guidelines
for Exercise Testing and Prescription, 6; 145.
Gaskill SE, et. al. (2004) %heart rate reserve is better
related to %VO2max than to VO2 Reserve: The Heritage Family Study.
Medicine & Science in Sports & Exercise, 36(5) S3.
Peterson, PA, Bryant, CX (1995) The StairMaster Fitness
Handbook, 2; 5-7.
Pollock ML (1973) The quantification of endurance training
programs. In Exercise and Sports Sciences Reviews, ed. JH Wilmore,
1: 155-188, New York; Academic Press.
Skinner JS, et. al. (2004) Evaluation on ACSM guidelines
on prescribing exercise intensity for "quite unfit":
The Heritage Family Study. Medicine & Science in Sports &
Exercise, 36(5) S3.
Tudor-Locke C, Pangrazi RP, Corbin CB, Rutherford WJ, Vincent
SD, Raustorp A, Tomson LM, Cuddihy TF 9 (2004). BMI-referenced
standards for recommended pedometer-determined steps/day in children.
Prev Med. Jun;38(6):857-64.
USDA (2005) Dietary Guidelines for Americans, viii.