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Physical activity: an old-fashioned remedy for the health challenges of the 21 st Century?. John Saxton Professor of Clinical Exercise Physiology University of East Anglia.
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Physical activity: an old-fashioned remedy for the health challenges of the 21st Century? John Saxton Professor of Clinical Exercise Physiology University of East Anglia
The World Health Organisation predicts that chronic conditions will be the leading cause of disability by 2020 and that, if not successfully managed, will become the most expensive problem for health care systems
In England, 15.4 million people are currently living with a chronic condition • It is estimated that up to three-quarters of those over 75 y are suffering from a chronic condition, and this figure continues to rise • By 2030, the estimate is that the incidence of chronic disease in the over 65s will more than double • The treatment of chronic conditions accounts for 70% of total health and social care costs
By 2034, it is projected that: • nearly a quarter (23%) of the UK population will be aged ≥65 y (from 16% in 2008) • 5% of the UK population will be ≥85 y Life expectancy (LE) versus Healthy Life Expectancy (HLE) Women Men 90 90 LE LE 81.6 80.4 77.4 75.7 76.8 80 80 HLE HLE 70.9 68.8 67 66.7 70 64.4 70 64.3 62.5 60 60 50 50 40 40 Age (years) Age (years) 30 30 20 20 10 10 0 0 1981 2001 2006-8 1981 2001 2006-8 Office for National Statistics 2011
The evolution of man and lifestyle behaviours from Homo erectus to Homo sapiens…
The world of today is not the environment we evolved in… Our lifestyles have been transformed from that of wandering hunter-gatherers to sedentary consumers of more than we need to survive from Homo erectus to Homo sapiens… ‘Homo sedentarius’ ‘Homo obesus’
Self-reported sedentary time Health Survey for England 2008, Volume 1: Physical activity and fitness Mean number of hours per working day in occupational activities, by sex
Prevalence of overweight and obesity Health Survey for England 2009, Volume 1: Health and Lifestyles
How important is the link between physical inactivity and chronic disease?
As early as the ninth century B.C., the ancient Indian system of medicine (Ayurveda) recommended exercise and massage for the treatment of rheumatism Greek philosopher Hippocrates (‘the father of medicine’) acknowledged the virtues of exercise for physical and mental health in the 4th century B.C.
World Health Organisation statistics • Physical inactivity is estimated to be the principal cause of ~30% of the ischaemic heart disease burden, ~27% of the diabetes burden and ~21-25% of the breast and colon cancer burdens (WHO 2009). • Worldwide, approximately 3.2 million deaths (6% of all deaths) each year are attributable to insufficient physical activity (WHO 2010).
Jerry N Morris 1910 - 2009 Bus drivers in their 40’s were nearly five times more likely to develop ischaemic heart disease than age-matched conductors(Morris et al. 1966; Lancet 2; 553-559). 40% reduced risk of fatal heart attack and a 50% reduction in non-fatal coronary events among British male civil servants who participated in vigorous exercise requiring peaks of energy expenditure (Morris et al. 1980; Lancet 2: 1207-1210). Ralph S Paffenbarger Jr 1922 - 2007 28% reduced risk of all-cause mortality among USA college alumni reporting a weekly exercise energy expenditure of 2000 kcal.week-1 (Paffenbarger et al. 1986; NEJM 314; 605-613). Steven N Blair 1939 - 7.9% decrease in all cause mortalityfor every 1 min improvement in treadmill walking time (roughly equivalent to 1 MET increase in aerobic exercise capacity) among men attending medical check-ups at the Cooper Clinic in Dallas USA (Blair et al. 1995; JAMA 273; 1093-1098).
WHO Global Recommendations on Physical Activity for Health (2010) • 150 minutes of moderate-intensity aerobic physical activity or 75 minutes of vigorous intensity aerobic physical activity throughout the week, or an equivalent combination of the two. • For additional health benefits, aim to increase this to 300 minutes of moderate aerobic physical activity or 150 minutes of vigorous-intensity aerobic physical activity per week or an equivalent combination of the two. • Aerobic activity should be performed in bouts of at least 10 minutes duration. • Muscle strengthening exercises (involving major muscle groups) on 2 or more days per week. • Limit the amount of time spent in sedentary activities
Objective physical activity levels Health Survey for England 2008, Volume 1: Physical activity and fitness
Environmental influences on physical activity!! Waiting to take the escalator
Behavioural influences on physical activity!! “Whenever I feel like exercise, I lie down until the feeling passes”
How can we get people to exercise at the right levels and in the right way to optimise the health benefits?
Exercise in the management of long-term conditions The role of exercise in ameliorating the impact of chronic disease, improving quality of life and survival
Perceived fatigue Muscular Motor Anxiety Depression Stress Morphological (Body composition) Perceived ability to cope Sense of control Health-related Quality of life & Disease-free survival Cardio-respiratory Self-esteem Social integration Metabolic Cognitive function Immunological Enjoyment of life Mood states Molecular Perceived Physical attractiveness Physiological Psychosocial
Key research questions: • Can exercise training counteract the adverse physiological and psychological consequences of disease and its treatments? • Function; quality of life; disease-free survival • In those with long-term conditions, what is the role of exercise in disease modification? How does exercise interact with drug treatments? Can exercise counteract the side-effects of drug treatments? • Why do some patients respond/adapt differently to exercise training? • What are the contra-indications to exercise in different clinical groups?
Where exercise has proven benefits to a clinical group – how can it be optimised?
INTENSITY FREQUENCY F-I-T-T PRINCIPLE TIME TYPE
Vignettes – the application of exercise science to the management of long-term conditions • Optimising exercise rehabilitation in terms of engagement and health benefits in peripheral arterial disease • Impact of exercise on quality of life and disease-free survival after cancer • Exercise and symptoms of clinical fatigue in multiple sclerosis
Peripheral arterial disease (intermittent claudication)
Affected arteries of the lower limb External iliac artery Aortic and iliac arteries 30% Femoral and popliteal arteries 80-90% Tibial and peroneal arteries 40-50% Femoral artery Popliteal artery Posterior tibial artery Anterior tibial artery Dorsalis pedis (palpation point)
TREATMENT STRATEGIES FOR IC • EXERCISE THERAPY • PHARMACOLOGICAL TREATMENTS • CV RISK FACTOR MODIFICATION • SURGICAL INTERVENTIONS “Stop smoking and keep walking”
Problem! A significant proportion of patients do not engage in walking exercise!!
Alternative exercise rehabilitation strategies - rationale Leg cranking exercise Arm cranking exercise • A large proportion (~ 35%) of patients exceed their leg-cycling aerobic exercise tolerance during arm-cranking exercise • Less exercise pain during arm-cranking, despite similar perceived exertion and higher blood lactate at maximal exercise tolerance Zwierska et al. (2006); EJVES
Calf muscle haemoglobin saturation during walking (NIRS) Pre Post NIRS time to minimum StO2 was increased after arm-cranking exercise training
Evidence of a reduction in systemic inflammation after arm-crank training Circulating hs-CRP Chi square analysis showed that the proportion of patients in the arm-cranking group with a favourable hs-CRP profile (defined as < 1.72 mg.l-1) was higher than in the control group at the 24-week time-point (50% vs 23%, respectively; P < 0.05). Saxton et al. (2008); EJVES
Impact on exercise pain tolerance Zwierska I et al. (2005). J Vasc Surg 42:1122-30.
Mechanisms? • Central cardiovascular adaptations? • Blood rheology (changes in viscosity)? • Exercise pain threshold/tolerance? • Improved blood flow/distribution linked to improved ability of lower limb arteries to dilate during exercise
Nordic pole walking (NPW) study • To investigate whether the use of Nordic poles leads to an improvement in common parameters of walking performance in patients with intermittent claudication • To compare the cardiopulmonary responses and level of leg-pain evoked by NPW with those evoked by normal walking exercise in this patient group
Experimental set-up and Methods • Methods • N = 20 patients with intermittent claudication recruited from SVI • Patients were familiarised with the NPW technique, allowed ample practice time, performed “dummy run” • Two treadmill walks: 3.2 km.h-1 @ 4% gradient in random order Wide belt H-P-Cosmos Saturn Treadmill
During NPW: The level of claudication pain at MWD was less despite higher oxygen consumption For 9/20 patients (45%), the NPW test was terminated for reasons other than claudication pain (e.g. breathlessness/ breathing hard, mouth dry, very tired, exhausted), versus only 1 in the normal walking condition These results suggest that NPW could be a useful ergogenic aid for improving the cardiopulmonary stimulus to exercise rehabilitation in claudicants
Cancer survivorship Treatment cycle Lifestyle behaviours influencing QoL / disease-free survival Disease recurrence / Second primary tumour Cancer diagnosis Recovery / rehabilitation Stages of the cancer experience Treatment / surveillance Pre-diagnosis End of life Lifestyle behaviours influencing risk Lifestyle behaviours influencing treatment outcome / QoL Lifestyle behaviours influencing QoL Time-line
% Risk reduction 60 10 20 30 40 50 70 80 90 0 Holmes et al. (2005) (Overall mortality) 9-14.9 MET-h/week moderate intensity PA Holmes et al. (2005) (Breast cancer mortality) 9-14.9 MET-h/week moderate intensity PA Pierce et al. (2007) (Overall mortality) 25 MET-h/week total recreational PA Breast cancer studies Holick et al. (2008) (Overall mortality) 4-10.2 MET-h/week moderate intensity PA Holick et al. (2008) (Breast cancer mortality) 4-10.2 MET-h/week moderate intensity PA Irwin et al. (2008) (Overall mortality) 150 min per week moderate intensity PA Meyerhardt et al. (2006a) (Disease recurrence or death) 18-26.9 MET-h/week total recreational PA Colorectal cancer studies Meyerhardt et al. (2006b) (Colorectal cancer mortality) 18 MET-h/week total recreational PA
% Risk reduction 60 10 20 30 40 50 70 80 90 0 Kenfield et al. (2011) (Overall mortality) ≥ 90 min/week normal/brisk pace walking Kenfield et al. (2011) (Prostate cancer mortality) ≥ 3 h/week vigorous activity Prostate cancer studies Richman et al. (2011) (Prostate cancer progression) ≥ 3 h/week brisk walking
Weight gain is a problem for breast cancer patients The majority of women gain weight and % body fat between 1-3 years post-diagnosis (Irwin et al. 2005; JCO 23, 774-782) • Mechanisms of weight gain? • Chemotherapy / endocrine therapy • Reduction in lean body mass and resting energy expenditure • Reduction in physical activity due to fatigue • Increased food ingestion – linked to coping mechanisms / treatment-related appetite