Chapter 11Ageing

Chapter overview

• Introduction

• Decline in functional capacities

• Exercise training and functional capacities

• Exercise, ageing and independent living

• Intervention trials of physical activity in the elderly

• Summary

Introduction

• Improvements in life expectancy mean more older individuals.

• Risk for many diseases increases with age and functional capacities inevitably decline.

• Cognitive function also declines with age.

• Many of the elderly are burdened with disease/disability that compromises quality of life and capability to live independently.

UK records for the marathon according to sex and age

Note: Data as at December 2006.

Decline in VO2max with age

Notes: Plain lines: cross-sectional data; lines with symbols: 20-year follow-up in track athletes.

Isokinetic muscle strength of knee extensors at different ages

Changes in weight and fatness over 30 years

Note: The five individuals took part in the ‘Dallas Bed-rest and Training Study’ in 1966 and were followed up in 1996.

VO2max in five men aged 20 pre- and post-training in 1966 – study repeated

in 1996

Increased capillary density in gastrocnemius muscle of 60–70-year-olds with 9–12 months of endurance training

Increased activity of oxidative enzymes of 60–70-year-olds with 9–12 months

of endurance training

Males Females

Pre-training

Post-training

Pre-training

Post-training

Succinate dehydrogenase 1.11 1.83 0.76 1.05

Citrate synthase 2.97 3.83 2.21 2.58

β-hydroxyacyl-CoA dehydrogenase 5.95 8.45 5.29 7.19

Strength of muscles around knee increased after 12 weeks of training

Note: Subjects were men aged 60–72.

Cross-sectional area of quadricep muscle increased after 12 weeks of

strength training

Note: Subjects were men aged 60–72.

Decline in functional capacities limits independent living

Decreases in functional capacities often go unnoticed until a threshold is reached when a person has difficulty performing a particular task, such as:• crossing a road in time allotted at crossing;

• getting up from a low chair;

• climbing a stair;

• opening the cap on a jar;

• putting socks on.

Regular, frequent physical activity ...

• improves balance, walking speed, stair climbing, time taken to rise from chair and get back down and general mobility;

• reduces morbidity and mortality from disease, e.g. CHD, CVD, stroke, cancer and neurological illnesses.

Ratio of rates of deaths in runners and healthy controls

Note: Subjects were aged 50 or older at baseline and followed annually for 21 years.

Walking and risk of hospitalization due to CVD in men and women aged 65 at baseline

Note: Average follow-up of 4.2 years.

Differences in change in cognitive scores by quintile of activity

Notes: Positive scores indicate reduced level of decline, relative to the least active reference group; n = 18,766 women aged 70–81.

Walking and incidence of dementia and Alzheimer’s disease

Note: Data from 2,257 physically capable men aged 71–93.

Association between leukocyte telomere length and leisure-time physical activity

levels in middle-aged people

Note: Telomeres are pieces of DNA at the end of chromosomes. Their length is an index of biological age – longer telomeres indicate lower biological age. n = 2,401

Influence of 12 weeks of weight training on leg strength and walking endurance in

healthy people aged 65–79

Note: Randomized controlled trial.

Changes (%) in frail nursing home residents aged 72–98 after ten weeks

of resistance training

Control group (N = 26)

Exercise group (N = 25)

Muscle strength 3 9 113 8

Walking speed –1 4 12 4

Stair-climbing power 4 7 28 7

Thigh muscle area –2 2 3 2

Note: Data are mean  SEM.

Summary I

• VO2max and muscle strength decline with age, as do flexibility, balance and general mobility. Body composition changes, with a decline in muscle mass and an increase in percentage fat.

• Loss of muscle mass explains the decline in muscle strength and may also explain a large portion of the decline in VO2max.

• Inactivity can contribute to the decline in functional capacities. Individuals who remain active are capable of high levels of physical performance into their eighth decade.

• The potential for adaptation to exercise training persists throughout life. Adaptations in the elderly are qualitatively similar to those evident in younger people.

Summary II

• The decline in functional capacities associated with ageing eventually impairs the ability to perform activities of daily living, leading to loss of independence and quality of life.

• An active lifestyle, particularly if it includes resistance training, can help to counter the age-related decline in functional capacities and mobility, reducing the risk of disease, disability and hospitalization and extending independent living.

• Cognitive function declines with age. Active older adults have a lower risk of dementia and Alzheimer’s disease. Evidence suggests that exercise intervention may enhance cognitive function in people at increased risk for these diseases.