Adaptations to Aerobic and Anaerobic Training

cardiorespiratory endurance

- Ability to sustain prolonged, dynamic exercise

- Improvements through multisystem adaptations (cardiovascular, respiratory, muscular, metabolic)

endurance training

↑ maximal endurance capacity = á V^•O_2max

– ↑ submaximal endurance capacity:

• Lower HR at same submaximal exercise intensity

heart size

– With training, ↑ heart mass and LV chamber size

– ↑ plasma volume = ↑ LV volume = ↑ EDV =  ↑ SV

– Volume loading effect vs pathology of hypertrophy from hypertension

SV ↑ after training

– Resting, submaximal, maximal

–Plasma volume ↑ with training = ↑ EDV =         ↑ preload

– Resting and submaximal HR ↓ with training =   ↑ filling time = ↑ EDV

– ↑ LV mass with training = ↑ force of contraction

resting HR

– ↓ markedly (~1 beat/min per week of training)

– ↑ parasympathetic, â sympathetic activity in heart

submaximal HR

– ↓ HR for same given absolute intensity

– More noticeable at higher submaximal intensities

maximal HR

– No significant change with training (may ↓ slightly)

– ↓ with age

HR recovery

– Faster with training

– Indirect index of cardiorespiratory fitness

Cardiac output (Q^•)

– Little or no change at rest or during submaximal exercise with training

–Maximal Q^• ↑ considerably (due to ↑ SV)

fiber type

↑ size and number of type I fibers

–Type IIa perform more like type I

–Type IIx may perform more like type IIa

capillary supply

↑ number of capillaries supplying each fiber

–May be key factor in V^•O_2max ↑

myoglobin

↑ myoglobin content by 75% to 80%

– Supporting ↑ oxidative capacity in muscle

respiratory exchange ratio (RER)

↓ at both absolute and relative submaximal intensities

– ↑ dependent on fat, ↓ dependent on glucose

lactate threshold

- ↑ to higher percentage of V^•O_2max  

- ↓ lactate production, ↑ lactate clearance

– LT occurring at approx. same absolute [LA]

resting and submaximal V^•O₂

– Resting V^•O₂ unchanged with training

– Submaximal V^•O₂ unchanged or ↓ slightly with training

Maximal V^•O₂ (V^•O_2max)

–Best indicator of cardiorespiratory fitness

– ↑ substantially with training (15%-20%)

– ↑ due to ↑ cardiac output and capillary density

more

_ people over age 50 are engaged in sport and exercise today than 30 years ago.

– Recreation

– Competition

– More fit than older sedentary counterparts

• Performance declines with age.

height ↓ with age

– Starting at 35-40 years

– Compression of intervertebral disks

– Poor posture

– Later: osteopenia, osteoporosis

weight ↑, then ↓

- ↑ 25-45 years: ↓ physical activity, ↑ caloric intake

– ↓ 65+ years: loss of body mass, ↓ appetite

body fat content

• tends to increase

– Active versus sedentary older adults: variation

– Older athletes ↓ body fat content

– Older athletes ↓ central adiposity

fat free mass

- ↓ starting around age 40.

– Due (in part) to lack of activity

– ↓ muscle, bone mass

– Sarcopenia (protein synthesis ↓)

– ↓ growth hormone, insulin-like growth factor 1

bone mineral content

decreases

– Bone resorption > bone synthesis

– Due to lack of weight-bearing exercise

body comp variables

– Body weight

– Percent body fat

– Fat mass

– Fat-free mass (FFM)

training

• alters age-related changes in body composition.

- ↓ weight, percent body fat, fat mass

– ↑ FFM (more likely with resistance training than with aerobic training)

– More in men than in women

• Biggest results come with diet + exercise.

strength and neuromuscular function

decreases with age

– Interferes with activities of daily living.

– Manifests at about 50-60 years of age.

– Results from ↓ muscle mass.

• Strength ↓ offset by resistance exercis

type ii fiber loss

• occurs with aging

– Decrease in type II motor neurons

– Higher percent type I fibers

• Training slows fiber-type change.

size and number of muscle fibers

• ↓ with age

– Size of both type I and type II ↓

– Loss of 10% per decade after age 50

• Endurance training → no impact on decline in muscle mass with age

• Resistance training = ↓ muscle atrophy, ↑ muscle cross-sectional area

reflexes

• slow with age.

– Exercise preserves reflex response time.

– Active older people ≈ young active people.

motor unit activation

• ↓ with age.

– Fewer MU activated = ↓ Force production

exercise

• maintains muscle physiology.

– Number of capillaries is unchanged.

– Oxidative enzyme activity is only mildly reduced.

mitochondrial function

• declines with age.

– Reduced mitochondrial protein synthesis

– Reduced maximal rate of ATP production

• May contribute to muscle atrophy.

– Increased intracellular oxidative stress interferes with myofilament function.

• Increased free radicals with aging

• Improved by exercise training.

central and peripheral cardiovascular

decrements with age

• Reduced maximal HR

– Reduction varies considerably

– Electrical changes with age

– Increased parasympathetic NS influence

– Same for active and sedentary people

maximal stroke volume (SV)

decreases with age

↓ contractility, response to catecholamines

– LV, arterial stiffening

– Decline in SV_max attenuated by exercise

V^•O_2max

• ↓ with age due to â Q^•_max

– Due more to â HR_max, less to â SV_max

- Decline inV^•O_2maxattenuated by exercise

sedentary habits

• ↑ risk for vascular aging

– ↓ cardiac and arterial compliance

– ↑ narrowing of arteries

– ↑ vasodilation