Transcript HEAT ACCLIMATIZATION

RACING AND AGEING:
WHAT IS THE REAL
ASSOCIATION?
Michael Turnbull
2nd November 2005
OVERVIEW
• The participation of adults over 40 in
competitive sport has increased dramatically.
• Triathlon has a highly competitive age-group
scene.
• However, ageing will lead to a decline in
performance.
OVERVIEW
• Areas to be addressed:
– Does ageing affect performance?
– Physiological changes and ageing
– How trainable are middle-aged athletes?
– Does intensive exercise pose any health risks?
SPORTING
PERFORMANCE
• Swimming
• 1500m times decline steadily from the age of 35
onwards.
• Cycling
• 40km times decrease at about an average of
20secs (0.6%) a year.
• Running
• A declination rate of about 1% per year from the
age of 27-47 can be seen in 10km times.
BODY SIZE
• Height is lost and weight is gained.
• Height loss can start to occur as early as 35.
• Weight gain generally begins between 25-45.
BODY COMPOSITION
• However, training can attenuate these changes
BODY COMPOSITION &
TRAINING
• Regular training in older athletes can maintain body
composition to similar levels as sedentary young people.
RELATIVE FAT MASS
(%)
40
35
30
25
20
Men
Women
15
10
5
0
Young
Sedentary
Older
Sedentary
Young
Trained
Older
Trained
STRENGTH
• Strength can decrease by approximately 1.8%
per year from 35 years.
• Maximal and dynamic strength is reduced.
• Active people experience a shift towards slow
twitch muscle fibres.
• The total number of muscle fibres and fibre
cross sectional areas decrease with age.
STRENGTH & TRAINING
• Strength and resistance training is an important
aspect.
• Research has shown that ageing does not
impair a person’s ability to increase muscle
strength or muscle hypertrophy.
• Individual muscle fibres also have the ability to
grow in size.
CARDIOVASCULAR
FUNCTION
• Endurance performance declines with age.
• Max HR decrease less than 1 beat per year
– HRmax = [208 – (0.7 x age)]
• Max stroke volume and cardiac output
decrease.
CV FUNCTION &
TRAINING
• Studies indicate that CV changes are minimized
in older athletes who continue to train.
• Stroke volume can be maintained in older
athletes who have continued to train.
• Physical inactivity plays a bigger part than the
ageing process.
RESPIRATORY FUNCTION
• Vital capacity and FEV decrease linearly with age
• Residual volume increases
• Maximal expiratory ventilation decreases.
• These are primarily caused by a loss of elasticity in
the lung tissue and the chest wall.
• Total lung volume remains unchanged
VO2 MAX
• Aerobic capacity decreases by approximately
1% per year.
• The primary limiter of VO2 max is the
decreased oxygen transport to the muscles.
• Similar results have been found for highly
trained endurance athletes - although the
variation is much wider.
VO2 MAX
CHANGES IN VO2 MAX AMONGST NORMAL
ACTIVE MEN
% change from
Age
VO2max
25 years
25
47.7
35
43.1
9.6
45
39.5
17.2
52
38.4
19.5
63
34.5
27.7
75
25.5
46.5
VO2 MAX & TRAINING
• High intensity training should not be reduced.
• High intensity training leads to significantly
smaller decreases in VO2 max.
• Endurance training improves muscle’s oxidative
enzyme activities.
EXPOSURE TO HEAT
• Older adults are more susceptible to fatal heat
injuries.
• There is a reduction in thermal tolerance and
regulation
• Even when people are matched for body size,
comp, VO2 max, and acclimatization, these age
related differences persist.
TRAINING ADAPTATIONS
• Endurance exercise training produces similar
gains in healthy people, regardless of their age,
sex or initial level of fitness
• Training cannot halt the process of biological
aging, but it can lessen the impact of ageing on
performance.
CONCLUSION
• Ageing affects physical performance
• Cardiorespiratory function, strength and body
composition are all impaired with age.
• It is clear that much of these changes is
attributable to inactivity.
• Physical activity leads to changes that are
similar to that seen in young adults.
• Age is not a barrier!