Download The trainability of elderly people

Age and Ageing 2002; 31: 223–224
#
2002, British Geriatrics Society
EDITORIAL
The trainability of elderly people
Studies of physical training to improve cardiorespiratory
fitness in people over 75 years of age are rare. The two
papers published in this issue of Age and Ageing by
Kallinen et al. [1] and Malbut et al. [2], are important for
all those involved in the training and rehabilitation of
elderly people. Training studies with elderly people are
difficult: the variability of the response to training means
that a notable mean improvement in fitness relative to
a control may not achieve statistical significance (see
Kallinen et al.). Attempts to maximise statistical power
(such as using each subject as their own control) may
actually create difficulties with data interpretation, (see
Malbut et al.). Interpretation is complicated by the
prevalence of chronic disease and medications, and
there is also the question of potential hazards associated
with training heterogeneous groups of frail elderly
people.
The results of the two studies are different: Kallinen
et al. did not show a statistically significant improvement
in the peak oxygen consumption (V·O2peak) of a group
of elderly female volunteers (taking an average of 2–3
medications each) after 18 weeks of training, despite
improvements of 7% and 9% in the training groups and
a 6% decline in the controls. (But post-hoc calculations
showed statistical ‘underpowering’). Malbut and her
colleagues studied healthy men and women and did
show a significant improvement in maximal oxygen
uptake (V·O2max.) after 24 weeks of training but only in
the women. It would appear that the men were not as
responsive as the women to training (although their data
are more difficult to interpret). Both studies expose
important issues regarding the method of measurement
of cardiorespiratory fitness and its responsiveness to
training.
The measurement of cardiorespiratory fitness
The first issue relates to the measurement of cardiorespiratory fitness. While V·O2max. is undoubtedly a
valid and reliable indicator (and indeed the ‘gold
standard’ measure) of cardiorespiratory fitness in young
healthy individuals, its choice as an outcome measure in
this type of study is questionable. While criteria for the
achievement of a true maximal value by older people
have been suggested, none has been universally adopted.
Since it requires a maximal exhaustive effort, V·O2max. is
difficult to measure in very elderly people on practical
grounds alone, but it may also be impossible in those
with chronic disease. In patient studies, a symptom
limited V·O2 is often used (V·O2peak) but this measurement could be presumed to be subject to even greater
variability. Perhaps it is time to shift the focus away
from a maximal or peak measurement to a submaximal
measurement which, while still measuring cardiorespiratory fitness, may be more achievable, reliable and
meaningful. A decreased heart-rate response to a given
submaximal value of oxygen uptake is a classical
response to endurance training and was demonstrated
in Malbut’s study by a significant reduction in heart
rate at a V·O2 of 10 ml.kg. 1min. 1. (One could argue
that if the peak values for heart rate and oxygen uptake
reported in Kallinen’s study were actually submaximal
values, then their results are also consistent with this
training response). Nevertheless, given the increased
prevalence of disease in old age and an increased use of
medications such as b-blockers and digoxin which
affect the interpretation of the heart rate response to
exercise, we need alternative submaximal indicators of
cardiorespiratory fitness which could be applied within
a heterogeneous elderly population.
Factors influencing the cardiorespiratory
response to training
A second issue relates to the influence of health status
upon the ability to respond to training. Participants in
Kallinen’s study had evidence of ischaemic heart disease,
hypertension, respiratory disease and musculoskeletal
problems. The results of this study therefore raise the
question of whether responsiveness to training is
diminished in the presence of some chronic diseases.
Although the evidence relating to older patients is
sparse, previous studies have shown that the muscles of
frail elderly people such as those in institutional care
and those recovering from hip fracture can respond
to strength training with improvements in strength,
power and functional ability [3–6]. With respect to
cardiorespiratory training in elderly patients, the picture
is unclear, due to the lack of research in this area.
Nevertheless, in one study of cardiac rehabilitation
which included an element of training, the improvement
in aerobic capacity in patients aged 75 and over was
proportionately at least as great as in patients under 60
years [7].
Could the negative results of Kallinen and the
question mark over the response of Malbut’s male
subjects, perhaps reflect that it is not groups who
differ in their responses to training, but individuals
223
C. Greig
within groups? The variability of the response of
V·O2max. to training within ‘older’ (60–71 years [8])
and young adults has been described and indicates that
within any training group, there may be a large variation
in the response. This phenomenon may have a genetic
basis: Recent advances in molecular biology have
enabled the identification of genes and their polymorphisms that contribute to differences in human physical
performance [9]. The most extensively studied ‘performance’ gene so far is the ACE gene. There is some
evidence from studies of young adults that ACE
genotype may influence the responsiveness to endurance
or strength training [10]. Studies of older adults have
yet to be reported, but the possibility of explaining
(and predicting) someone’s responsiveness to training
(including therapeutic exercise) on the basis of their
genotype, is becoming less remote.
Can elderly people be trained safely
and effectively?
Kallinen and colleagues report adverse changes in the
health of several of their volunteers. They question
whether these could have been caused by physical
training and state the need for more research on the
dose-response relationship. This is essential if training
programmes are to be adapted to the needs of the
individual, in order to minimise risk and maximise
benefit [11]. In addition, further research should test
whether some pathologies (or medications) limit a
patient’s ability to respond to training. Then, perhaps
we will be better able to use physical training as a safe
and effective countermeasure against physical frailty.
CAROLYN GREIG
Geriatric Medicine, The University of Edinburgh,
21 Chalmers Street,
Edinburgh EH3 9EW, UK
Fax: (q44) 131 536 4536
Email: [email protected]
224
References
1. Kallinen M, Sipila S, Alen M, Suominen H. Improving
cardiovascular fitness by strength or endurance training in
women aged 76–78 years. A population-based randomized
controlled trial. Age Ageing 2002; 31: 247–54.
2. Malbut KE, Dinan S, Young A. Aerobic training in the
‘oldest old’: The effect of 24 weeks of training. Age Ageing
2002; 31: 255– 60.
3. Fiatarone MA, O’Neill EF, Ryan ND et al. Exercise training
and nutritional supplementation for physical frailty in very
elderly people. N Engl J Med 1994; 330: 1769–75.
4. McMurdo MET, Rennie LM. Improvements in
quadriceps strength with regular seated exercise in the
institutionalised elderly. Arch Phys Med Rehabil 1994; 75: 600–3.
5. Sherrington C, Lord SR. Home exercise to improve
strength and walking velocity after hip fracture: a
randomised controlled trial. Arch Phys Med Rehabil 1997;
78: 208–12.
6. Mitchell S, Stott DJ, Martin B et al. Randomized controlled
trial of quadriceps training after proximal femoral fracture.
Clin Rehabil 2001; 15: 282–90.
7. Lavie CJ, Milani RV. Effects of cardiac rehabilitation and
exercise programs in patients 075 years of age. Am J Cardiol
1996; 78: 675–7.
8. Kohrt WM, Malley MT, Coggan AR et al. Effects of
gender, age and fitness level on response of V·O2max.
to training in 60–71 yr olds. J Appl Physiol 1991; 71:
2004–11.
9. Rankinen T, Perusse L, Rauramaa R, Rivera MA, Wolfarth
B, Bouchard C. The human gene map for performance and
health-related fitness phenotypes. Med Sci Sports Exerc 2000;
33: 855–67.
10. Montgomery H, Clarkson P, Barnard M et al.
Angiotensin-converting-enzyme gene insertion/deletion polymorphism and response to physical training. Lancet 1999;
353: 541–5.
11. Dinan S. Delivering an exercise prescription for vulnerable
older patients. In Young A, Harries M eds. Physical Activity for
Patients; An Exercise Prescription. London: Royal College of
Physicians of London, 2001; pp 53–70.