Evidence of Benefit
We monitor the evidence base for the benefits and harms of walking and funded two comprehensive reviews which are reproduced below. In 2012 William Buckland, the Director of the National Campaign for Walking produced a report for Public Health England and the Ramblers which reinforced the strength of the evidence base - the evidence is very strong that the benefits are considerable and the risks negligible
HEALTH BENEFITS OF WALKING – THE EVIDENCE BASE
Prepared by Nick Cavill and Charlie Foster
For the National Campaign for Walking funded by the Department of Health, NHS London and Knowledge Into Action
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Charlie Foster & Nick Cavill |
25/6/2008 |
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Charlie Foster & Nick Cavill |
21/2/2009 |
2 papers by Allender added |
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HEALTH BENEFITS OF WALKING – THE EVIDENCE BASE
“Walking is the nearest activity to perfect exercise”. Professor J Morris and Dr Adrianne Hardman, 1997[i]
1 Introduction
There is now overwhelming evidence about the associations between regular physical activity and a reduction in risk of death, and risk of major diseases like CVD, stroke and diabetes. It contributes to well being and is essential for good health. The considerable evidence base for the links between physical activity and health were reported in the Chief Medical Officer’s (CMO) report[ii].
In many studies, walking is merged with other activities to generate an overall composite measure of physical activity. As walking is one of the most common types of physical activity, we could refer to the evidence that links total physical activity to health outcomes assume that it can be extrapolated to walking. However, there is now sufficient evidence on the independent benefits of walking to health outcomes.
In this report we therefore do not rely solely on evidence about the relationship between physical activity and health and apply that to walking. Wherever possible, we rely on evidence that specifically links walking and health outcomes.
2 The impact of walking on fitness, strength, flexibility and stability of joints
Walking gently stresses the body’s key systems (heart and lungs, muscles, joints and circulation). This stress leads to the body adapting to accommodate the increased demands on it – i.e. becoming fitter. Walking stresses the body at a level that is considered very beneficial to overall health and fitness but is within the reach and ability of all adults and children.
It is important to remember that walking at 3 mph uses up only 30% of the maximum energy consumption of a person aged 25. But, as this decreases by 10% a decade, a person aged 75 walking at the same speed uses up 60% of his / her maximum energy. This principle is central to walking advice or prescription.
Brisk walking can improve cardiovascular fitness[iii]. Even 10-minute brisk walks can increase fitness. One study reported that women walking continuously for 30 minutes on 5 days a week had almost identical increases in fitness as women who split their 30 minutes into three 10-minute walks[iv]. Some younger men and most other adults would improve their fitness if they took up regular brisk walking[v].
We have estimated that encouraging the adult population to walk at 3 mph instead of their slower usual pace would be sufficient to improve their levels of cardiovascular fitness. This message would be appropriate for approximately 6.3 million English adults or 23% of all adults aged 16-74 years (using data from the 1990 National Fitness Survey[vi]. Figure 6 illustrates this.
Figure 6: Average levels of fitness for both genders at different age groups with the reach of brisk walking and its potential impact on improving fitness
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Brisk walking
would improve fitness for these adults |
As muscle strength declines with aging, regular brisk walking can maintain functional capacity and muscle strength. For both men and women there is a strong relationship between stronger muscle strength and brisker preferred walking speed[vii].
Walking and other physical activities can increase joint range of motion, particularly for older adults. Stronger muscles, joints and general flexibility developed and maintained by walking can reduce the likelihood of fallsii. The risks of injury by participating in walking are extremely small[viii].
3 Mortality and walking
Walking more can bring substantial benefit to health. This benefit is quantified by comparing the risk of specific diseases between people who walk with people who don’t walk. There is a clear dose-response relationship between walking and all-cause mortality[ix]. A physical activity energy expenditure of 500-1,000 kcals per week (about 6-12 miles of walking for an average-weight individual, compatible with the current physical activity recommendations for adults) reduces the risk of premature death by 20-30%ii.
From a public health perspective, helping people to move from a low level of walking to increasing walking levels will produce the greatest reduction in risk. These considerable health benefits hold for both women and men and are evident even up to the age of 80 years. The reduction in relative risk of mortality for adults walking more than 12.4 miles per week compared to adults who walked less than 3 miles per week is 16%[x].
Regular walking across the life course (from childhood to old age) will reduce risk of disease and pre-mature deathi. Figure 7 shows the difference in risk between an active / regular walker and less active / non-walker. The top line (unhealthy non-walker) shows the negative and cumulative effects of inactivity, low fitness and a higher risk of premature illness across the life course.
Figure 7: Risk of disease throughout the life course among walkers and non-walkers
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Regular walker |
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Non walker |
4 Prevention of diseases and risk factors for disease
Walking reduces the risk of many diseases.
The benefits of physical activity can be gained from activities that can be incorporated into everyday life, such as regular brisk walking…Physical activity does not need to be vigorous to confer protectioniv
Chief Medical Officer 2004 – CMO Report, page 38
Figure 8 represents this.
Figure 8: Schematic representation of the dose-response relationship between walking and physical activity level and risk of diseaseii
Walking and recovery from illness
Walking is now commonly recommended by doctors as part of recovery from illness or post operative. For example using walking as an exercise therapy can improve long term conditions such as for people with peripheral vascular disease[xi].
5 Long-term conditions
There are 15 million people in England with a long-term condition[xii]. These conditions account for 80% of the NHS Budget, 80% of GP workload and 60% of hospital inpatient activity. Those over 75 years of age make up 7.6% of the population. 75% of these have a long-term condition.
The main long-term conditions seen in primary care respond to physical activity both in prevention and treatment. These are outlined below:
Coronary Heart Disease
CHD causes over 101,000 deaths per year, one in five deaths in men and one in six deaths in women. It causes 20% and 11% of premature deaths in men and women respectively.
There are 2.6 million people living with CHD (i.e. angina, MI) in the UK.
The total cost of CHD to the economy is £7.9 billion, with 45% due to direct healthcare costs, 40% in productivity losses and 16% due to the costs of informal care.[xiii]
The cost of ischaemic heart disease to the NHS due to physical inactivity has been estimated at 23% of a total spend of £2.3 billion[xiv]. The Foresight report [xv] estimates direct NHS costs of CHD in 2007 to be £3.9 billion, suggesting the total NHS cost of CHD due to physical inactivity to be just over £1 billion.
The effect of walking on CHD is as follows[xvi]:
Increased maximal oxygen consumption
Relief of angina symptoms
Increased heart rate variability
Reduces Blood Pressure
Reduces body fat
Increases fibrinolysis
Increases levels of HDL
Improves glucose-insulin dynamics.
Improved psychological wellbeing
Protection from triggering an MI from vigorous activity >6 METS
For a healthy, young or middle-aged person, walking at a ‘normal’ to ‘brisk’ walking pace is enough to reduce the risk of cardiovascular disease and to improve risk factors for cardiovascular diseaseii.
Walking more than four hours per week reduces the risk of hospitalisation for cardiovascular disease by 30% compared to walking less than one hour per week[xvii]. The incidence of CHD is halved by walking over 1.5 miles a day in men compared to men who walked less distance per day[xviii]. Women who walked for exercise for about hours per week enjoyed a 35% reduction in their risk of CHD events compared to women who walked infrequently[xix].
Brisk walking of more than 3.5 hours a week may slow an atheroma, and walking five hours a week may slowly reverse its formation[xx].
Regular brisk risk walking reduces diastolic blood pressure but appears to have no effect on systolic blood pressureii.
Brisk walking for 8-15 miles per week for 6-9 months can increase good cholesterol levels (HDL) and reduce triglyceride levels in the blood[xxi]. Regular stair climbing has been reported to cause increases in HDL cholesterol, and a reduced ratio of total cholesterol to HDL cholesterol[xxii].
Heart Failure
There are about 900,000 people with heart failure in the UK, with a steep increase in age from 1% in those under 65 to 15% of those over 85[xxiii].
The total cost of treating heart failure in the NHS is £628.6 million, with the 86,000 hospital admissions accounting for over 60% of these costs[xxiv].
There are over 7.6 million GP consultations every year for heart failure, costing £103 million[xxv].
Most of the symptoms of heart failure are due to poor perfusion in the peripheral muscles secondary to limited cardiac output. Exercise limitation is usually from leg weakness due to lactate accumulation, leading to shortness of breath because of resulting acidosis. Regular walking therefore improves the peripheral muscle metabolism more than it affects the cardiac output. Regular walking as part of a rehabilitation programme significantly enhances quality of life, helps to retain independence and reduces hospital admissions.
Stroke
There are 68,400 strokes each year in the UK, causing 55,000 deaths and costing the NHS £1.36 billion.
Patients who have had a stroke are usually highly de-conditioned, with half the average VO2 maximum.
After a stroke regular walking can increase self-selected walking speed, reduce dependence on external aids (so maintaining independence), and reduce fatigue.
One study reported a decreased risk for stroke across increasing categories of walking pace in women[xxvi].
Most patients who have had a stroke will be encouraged to walk through their physiotherapy-led rehabilitation. There appears to be less structured walking programme for stroke patients. NICE will publish guidelines on stroke rehabilitation in 2009
Diabetes
There are 2.2 million people with diabetes in England (4.48% of the population) [xxvii]
This will increase to 3.6 million by 2025 (64% increase)
Half this increase is from the rise in obesity.
The effects of walking on diabetes include:
Improvement in blood sugar control
Improved insulin sensitivity
Reduction in body fat
Cardiovascular protection
Stress reduction (Stress can disrupt diabetes control by increasing counter-regulatory hormones, ketones and free fatty acids)
Prevention of diabetes in those at high risk[xxviii].
Walking and cycling levels are also associated with reduced risk of type 2 diabetes: those who walk or cycle more are less likely to get type 2 diabetes[xxix]. Walking and other changes can be a better option for helping to manage diabetes in some patients than drugs. The lifestyle changes in diet and increases in daily walking were found to be more effective in reducing the incidence of type 2 diabetes than treatment with the drug metformin (58% versus 31% reduction in risk)[xxx].
Chronic Obstructive Pulmonary Disease (COPD)
900,000 people have a diagnosis of COPD, with half as many again living with COPD without a diagnosis.[xxxi]
There are 109,000 COPD admissions, contributing to one million bed days costing the NHS £600 million, with a total cost to the NHS of about £1 billion.
COPD causes 24 million lost working days per year.
COPD patients who undertake more walking halve their risk of being admitted as an emergency admission.[xxxii] NICE guidance requires that all COPD patients who can walk attend Pulmonary Rehabilitation (PR). Patients in PR are recommended to walk regularly but there are only isolated schemes that link with organised walking groups. Regular exercise in groups reduces breathlessness and anxiety and increases confidence and independence.
Depression and Anxiety
Every day, 25,000 people see their GP with a psychological problem.
16.7% of the population suffer from Depression and Anxiety at any one time.
In 2005, 27.7 million antidepressant prescriptions were written in England, costing £338 million.
The cost of depression in lost economic output is £12 billion a year[xxxiii].
There is doubt whether most anti depressants are any better than Placebo.[xxxiv]
The Chief Medical Officer states that ‘Physical activity is effective in the treatment of clinical depression and can be as successful as psychotherapy or medication’ii.
NICE recommends that patients with mild depression follow a structured and supervised exercise programme of up to three sessions per week of moderate duration (45 minutes to one hour) for between 10 and 12 weeks. Walking might contribute to this type of regime[xxxv].
Walking can improve self-esteem, relieve symptoms of depression and anxiety, and improve mood[xxxvi]. There is an inverse relationship between daily walking and the reporting of depressive symptoms[xxxvii]. Shorter bouts (10-15 minutes) of brisk walking can induce significant positive changes in mood.
Osteoarthritis
Osteoarthritis of the knee and hip is the single most important cause of disability in retirement years, affecting up to 25% of those over 65.
The annual cost of treatment to the NHS is £675 million.
There are 36 million days lost due to osteoarthritis, costing the economy £3.2 billion in lost earnings.
Regular walking to build up the quadriceps muscles and help reduce weight is the cornerstone of both preventing and reducing symptoms of osteoarthritis of the hip and knee. Three 40-minute walks a week may help to halt the progression of knee osteoarthritis[xxxviii]. Regular walking and other moderate physical activities may be associated with a lower risk of subsequent osteoarthritis, especially among women.[xxxix]
Ironically, most GPs we spoke to said that the most frequent reason why overweight patients with osteoarthritis of the knee could not walk more was because of pain.
Obesity
24% of the population is obese and by 2050 60% of males and 50% of females will be obese.
In men, 18% of social class I and 28% in social class V are obese.
In women 10% of social class I and 25% in social class V are obese.
The current NHS cost is £1 billion with a projection of £6.5 billion in 2050.
The wider cost of obesity is £7 billion, rising to £45.5 billion in 2050.
Obesity is associated with diabetes, hypertension, asthma, osteoarthritis, depression and hyperlipidaemia. All of these are independently improved by regular walking.
Walking uses up about 100kCal per mile regardless of pace. Abdominal weight gain has been reported to be less than peripheral gain for women who walked >4 hours a week than women who walk less than 2 hours.
Below two hours a week walking there appears to be no weight loss.
Walking one hour a day for five days a week at 50-70% VO2 max can promote regional fat loss in the abdominal sites[xl]. This is critical in reducing the risk of diabetes and coronary heart disease. Overall weight may change little as lean body mass increases with exercise. Brisk walking reduces BMI and body weight,and also reduces body compositionii.
Any walking will help children and young adults to maintain energy balance[xli]. Any consistent movement of body weight by regular walking or stair-climbing will contribute to energy expenditure and may help with weight management.
Obesity is the single most common reason for GPs to refer patients for walking schemes and exercise referral schemes.
Walking and Cancer
Fewer studies have examined this relationship compared to other diseases, and the majority has only looked at physical activity rather than walking alone. However there is evidence that physical inactivity is associated with increased risk of colonic, breast (postmenopausal) and endometrium cancer. A faster reported walking pace was associated with a reduced risk of colorectal cancer in men compared to men with a slower walking pace than others[xlii].
6 Walking and children’s health
The Chief Medical Officer has pointed out that there is a strong justification for encouraging young people to be physically active. Physical activity provides an important vehicle for play and recreation, learning physical and social skills,
developing creative intelligence and stimulating growth and fitness.
However, there is relatively little direct evidence (compared with adults) linking physical inactivity in children with childhood health outcomes. The chronic diseases described above require long incubation periods, and children and adolescents very rarely have lifestyle-related diseases such as hypertension, diabetes, osteoporosis or cardiovascular disease.
Promotion of physical activity and walking in childhood does have strong justification however. It:
Promotes healthy growth and development of the musculoskeletal and cardio-respiratory systems
Helps maintain energy balance and hence healthy weight
Lowers risk of hypertension and high cholesterol
Generates opportunities for social interaction, achievement and mental well-being.
Walking is an excellent activity for all of these benefits. In addition, it may be that walking patterns track better into adulthood than do sport and leisure pursuits.
7 Economic value of walking
There is currently no economic evaluation of walking.
WHO has recently published guidance on including health effects in economic appraisals of transport interventions[xliii]. This was designed primarily to help transport economists estimate the mortality (and therefore economic) benefits of interventions that increased walking and cycling (such as new footpaths, policies or programmes). The rationale for this work is that 35% of all energy demand is from transport and 80% of this is in road transport. The transport sector is projected to be responsible for 90% of the increase in CO2 emissions until 2010.
The WHO guidance covered walking and cycling but the subsequent Excel model focused only on cycling. WHO is now proposing to extend this model to include walking to provide a practical tool that can be used at local, national and international level to make the case for walking.
This represents an opportunity to strengthen the approach taken to provide an economic appraisal and provide a strong, evidence-based arguments to advocate walking to key policy-makers.
[i] Hardman AE, Morris JN. Walking to health. British Journal of Sports Medicine 1998 Jun;32(2):184
[ii] Department of Health (2004). At least five a week: a report from the Chief Medical Officer. London, Department of Health.
[iii] Murphy MH, Nevill AM, Murtagh EM, Holder RL. The effect of walking on fitness, fatness and resting blood pressure: a meta-analysis of randomized, controlled trials. Preventive Medicine 2007; 44:377-385.
[iv] M Murphy and A E Hardman 1998, ‘Training effects of short and long bouts of brisk walking in sedentary women’ in Medicine and Science in Sports and Exercise 30:1:152-7
[v] Killoran AJ, Fentem P, Caspersen C. Moving on: an international perspectives on promoting physical activity. London: Health Education Authority, 1994.
[vi] Sports Council, Health Education Authority, 1992. Allied Dunbar national fitness survey. Health Education Authority, London.
[vii] American College of Sports Medicine. Exercise and Physical Activity for Older Adults. Medicine & Science in Sports & Exercise 1998. http://www.acsm.org/Content/NavigationMenu/Research/Roundtables_Specialty_Conf/PastRoundtables/Exercise_for_Older_Adults.htm
[viii] Sandolin J, Santavirta, Lattila R, Vuolle P, Sarna S. Sport injuries in a large urban population: Occurrence and epidemiological aspects. International Journal of Sports Medicine 1988; 9:61-66.
[ix] Lee IM, Skerrett PJ. Physical activity and all cause mortality: what is the dose-response relation? Medicine and Science in Sports and Exercise 2001; 33: S459-S471; discussion S493-S494.
[x] Lee I, Paffenbarger R. Physical activity and stroke incidence: the Harvard Alumni Health Study. Stroke 1998;29:2049-54.
[xi] Gardner AW, Poehlman ET. Exercise rehabilitation programs for the treatment of claudication pain. A meta-analysis. Journal of the American Medical Association 1995; 274: 975-980.
[xii] Our Health, Our Care, Our Say (2006) Department of Health
[xiii] Allender S, Peto V, Scarborough P, Kaur A, Rayner M. Coronary heart disease statistics 2008. London: British Heart Foundation, 2008.
[xiv]Allender S, Foster C, Scarborough P, Rayner M. The burden of physical activity related ill health in the UK. Journal of Epidemiology and Community Health 2007; 61:344-348.
[xv] Tackling Obesities: Future Choices – Modelling Future trends in obesity & their impact on Health. A Foresight report for Government Office for Science.
[xvi] ACSM’s Exercise management for persons with chronic diseases and disabilities. Durstine JL Moore GE 2002.
[xvii] LaCroix AZ, Leveille SG, hecht JA, Grothaus LC, Wagner EH. Does walking decrease the risk of cardiovascular disease hospitalizations and death in older adults? Journal of American Geriatric Society 1996; 44: 113-120.
[xviii] Hakim AA, Curb JD, Petrovitch H, Rodriguez BL, Yano K, Ross GW, White LR, Abbott RD. Effects of walking on cornary heart disease in elderly men: The Honolulu Hart Program. Circulation 1999;100:9-13.
[xix] Manson JE, Hu FB, Rich-Edwards JW, Colditz GA, Stampfer MJ, Willet WC, Speizer FE, Hennekens CH. A prospective study of walking as compared with vigorous exercise in the prevention of coronary heart disease in women. New England Journal of Medicine 1999; 341:650-658.
[xx] Hambrecht R, Niebauer J, Marburger C, Grunze M, Kalberer B, Hauer K, Schlierf G, Kubler W, Schuler G. (1993) Various intensities of leisure time physical activity in patients with coronary artery disease: effects on cardiorespiratory fitness and progression of coronary atherosclerotic lesions. J Am Coll Cardiol; 22 (2):478-9.
[xxi] Dishman RK, Washburn RA, Heath GW. Physical activity epidemiology. Champaign, Human Kinetics 2004.
[xxii] Boreham CA, Wallace WF, Nevill A. Training effects of accumulated daily stair-climbing exercise in previously sedentary young women. Preventive Medicine 2000; 30: 277- 281.
[xxiii] Ellis C, Gnani S and Majeed A (2001) Prevalence and management of heart failure in general Practice in England and Wales 1994-1998. Health Statistics Quarterly 11: 17-24.
[xxiv] DH (2002) Hospital Episode Statistics 2000-2001
[xxv] Gnani S et al (2001) Health Statistics Quarterly; Netten et al (1999) PSSRU, University of Kent.
[xxvi] Hu FB, Stampfer MJ, Colditz GA, Ascherio A, Rexrode KM, Willett WC, et al. Physical activity and risk of stroke in women. Journal of the American Medical Association 2000; 283: 2961-2967.
[xxvii] Yorkshire and Humber PHO. Diabetes – key facts, Yorkshire and Humber PHO, 2005.
[xxviii] ACSM’s Exercise Management for persons with Chronic Diseases and disabilities. Human Kinetics 2002.
[xxix] Hu FB, Sigal RJ, Rich-Edwards JW, Colditz GA, Solomon CG, Willett WC, et al. Walking compared with vigorous physical activity and risk of type 2 diabetes in women. Journal of the American Medical Association 1999; 282: 1433-1439.
[xxx] Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes with lifestyle intervention of metformin. New England Journal of Medicine 2002; 346: 393- 403.
[xxxi] NICE Guidelines on COPD management. Thorax 2004;59(suppl 1); 1-232.
[xxxii] Garcia-Aymerich J, Farrer E, et al Risk factors of readmission to hospital for a COPD exacerbation: A Prospective Study. Thorax 2003;58:100-105.
[xxxiii] LSE The Depression Report The Centre for Economic Performance’s Mental Health Policy Group June 2006
[xxxiv] Moncrieff J, Kirsch I Efficacy of antidepressants in adults. BMJ 2005, 331 155-9
[xxxv] NICE. Depression, NICE Guideline, Second Consultation. London: NHS, 2003, p19, 21.
[xxxvi] See MIND at http://www.mind.org.uk/Information/Booklets/Mind+guide+to/Mindguidetophysicalactivity.htm
[xxxvii] Mobily, K. E., L. M. Rubenstein, J. H. Lemke, M. W. O’Hara, and R. B. WALLACE. Walking and depression in a cohort of older adults: the Iowa 65+ rural health study. J. Aging Physiol. Activ. 4:119-135, 1996
[xxxviii] Ettinger Jr WH, Burns R, Messier SP, Applegate W, Rejeski WJ, Morgan T, et al. A randomized trial comparing aerobic exercise and resistance exercise with a health education program in older adults with knee osteoarthritis. The Fitness Arthritis and Seniors Trial (FAST). Journal of the American Medical Association 1997; 277: 25-31.
[xxxix] Rogers LQ, Macera CA, Hootman JM, Ainsworth BE, Blair SN. The association between joint stress from physical activity and self-reported osteoarthritis: an analysis of the Cooper Clinic data. Osteoarthritis and Cartilage 2002; 10: 617-622.
[xl] ACSM Exercise Management for persons with chronic diseases and disabilities Ch 23
[xli] The Health of Children and Young People 2003. Chapter 4: Physical Activity
[xlii] Davey Smith G, Shipley M, Batty G et al. Physical activity and cause-specific mortality in the Whitehall study. Public Health 2000;114:308-315.
[xliii] Cavill N, Kahlmeier S, Rutter H, Racioppi F, Oja P. (2008) Economic assessment of Transport Infrastructure and Policies: Methodological guidance on the economic appraisal of Health effects related to Walking and cycling. Rome. World health organization. Http://www.euro.who.int/transport/policy/20070503_1
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