Regular moderate-to-vigorous physical activity (MVPA) has been shown to be associated with lower risks of all-cause and coronary heart disease mortality (1,2). Furthermore, physically active lifestyles have been associated with a lower incidence of obesity (3) and type 2 diabetes mellitus (4). Increasing one’s physical activity has been considered an important strategy to reduce health risks (5).
The World Health Organization stated in its physical activity guidelines that adults should partake in at least 150 min of moderate-intensity aerobic physical activity (MPA) throughout the week or at least 75 min of vigorous-intensity aerobic physical activity (VPA) throughout the week, or an equivalent combination of moderate- and vigorous-intensity activity (6). However, the guideline does not provide any information on whether individuals can derive equal health benefits from any of these three patterns.
Several cohort studies have examined the intensities of physical activity considered optimal for longevity, but their results are inconsistent. Some reports showed that engaging in VPA had a more beneficial effect on mortality (7–11), whereas two others reported that longevity was associated more significantly with MPA than with VPA (12,13).
The Physical Activity Guidelines Advisory Committee Report stated in its executive summary that “it should be noted that an increase in intensity was often associated with an increase in volume of activity for many observational and experimental studies, and it is difficult to separate the benefits of each,” and also stated in its research recommendation that “inadequate data are available to answer a number of questions about dose response for a variety of health outcomes, such as the effects of activity intensity, bout duration, or frequency when total amount or volume of activity is held constant” (14).
It has thus been unclear whether equivalent health benefit is derived through three patterns recommended in physical activity guidelines. Therefore, the aim of this study is to examine the association between three different patterns of activity (i.e., three patterns of recommendation given in the physical activity guideline) and all-cause mortality in a population-based cohort study in Japan.
The Japan Public Health Center–based prospective study was started in 1990–1994, and detailed survey procedures have been explained elsewhere (15). In brief, it targeted all registered Japanese inhabitants in 11 public health center areas who were 40–69 yr of age at the start of the baseline survey. The participants were informed of the objectives of the study, and those who completed the survey questionnaire were regarded as consenting to participate. This survey was conducted at baseline and at 5-yr (second) and 10-yr (third) follow-up sessions. The study protocol was approved by the institutional review board of the National Cancer Center, Japan, and by the Tokyo Medical University Ethics Committee. Questions about detailed physical activity data (i.e., intensity, frequency, and time) were asked in the third survey only, thereby making this survey the starting point of our present study.
At baseline, 140,420 individuals were identified in the study population. After excluding 275 persons with non-Japanese nationality (n = 51), duplicate enrollment (n = 10), a late report of emigration occurring before the start of the baseline study (n = 207), and ineligibility owing to an incorrect birth date (n = 7), a population-based cohort of 140,145 individuals was established. After further excluding 8492 persons who had died or moved out of Japan, 131,653 subjects remained before the third follow-up survey, A total of 99,447 subjects responded to the third survey, yielding a response rate of 76%. By using data from the second survey, we observed no significant differences in baseline characteristics between responders and nonresponders in the third survey.
In addition, subjects with a history of cancer (n = 4683) or cardiovascular disease (n = 5801) and those with physical limitations (n = 2952) or missing data (n = 2557) were excluded. After exclusion, 83,454 (38,598 men and 44,856 women) were eligible for analysis. The flow diagram of categorized participants is shown in Figure 1.
Participants were followed from the starting point until December 31, 2012. Changes in residence status and survival were confirmed annually by residential registry. All death certificates were forwarded centrally to the Ministry of Health, Welfare and Labor and coded for the National Vital Statistics. In Japan, the registration of deaths is required by the Family Registration Law and is believed to be complete. Information on the cause of death for deceased subjects was obtained from death certificates provided by the Ministry of Health, Labour and Welfare, with permission, in which the cause of death was defined according to the International Classification of Diseases, 10th Revision.
Measurement of physical activity
Subjects were asked “How often do you engage in the following activities in your leisure time?” for 1) slow walking, 2) brisk walking, 3) moderate intensity of activity such as playing golf or gardening, and 4) vigorous intensity of activity such as jogging or playing tennis. They were then asked the frequency: 1) less than once per month, 2) 1–3 times per month, 3) 1–2 times per week, 4) 3–4 times per week, and 5) almost every day, and duration: 1) <30 min, 2) 30–59 min, 3) 1–2 h, 4) 2–3 h, 5) 3–4 h, and 6) ≥4 h.
According to the guideline, the present study defined “brisk walking” and “moderate intensity of activity” as MPA, and “vigorous intensity of activity” as VPA in leisure time (16). The average time of MPA and VPA in leisure time (min·wk−1) was determined by multiplying frequency and duration. To calculate subjects’ leisure time MVPA (MET·min·wk−1), the midpoint of the range for each category was assigned. When minimum and maximum values were presented on the questionnaire, boundary values were assigned in the highest or lowest categories. We then conservatively assigned 3.0 and 6.0 METs to MPA and VPA, respectively, and multiplied this by the average time (min·wk−1). In a validation study conducted among a sample of 110 participants from the cohort, acceptable test–retest reliability (r = 0.67 for two questionnaires administered 3 months apart) and validity (r = 0.68 compared with 24-h physical activity records) was found.
We used the current physical activity guideline to distinguish “physically active” or “physically inactive” subjects (i.e., <450 MET·min·wk−1) (6). We then classified “physically active” subjects (i.e., ≥450 MET·min·wk−1) into three groups by the proportion of VPA to total MVPA, that is, “0% VPA,” “30% or less,” and “more than 30%” in line with a previous study protocol (11).
Covariates and subject selection
Each survey gathered information on medical history and health-related behaviors. Covariates used in this study are age (continuous), residential area (10 public health areas), body mass index (<18.5, 18.5–25, or ≥25 kg·m−2), currently smoking (yes/no), excess alcohol intake (<60 or ≥60 g ethanol·d−1), currently having or with history of diabetes (yes/no), and currently having or with history of hypertension (yes/no).
Regarding physical limitation, participants were asked “How is your physical condition in daily life?” and were given the following choices of answer: 1) no limitation; 2) slight limitation, but can drive vehicles or take public transportation alone; 3) slight limitation, but can walk around the neighborhood; 4) partially limited, but can go out with some assistance; 5) partially limited, and seldom go out; 6) moderately limited and use a wheelchair, but eat or evacuate by themselves; 7) moderately limited and need assistance to get into a wheelchair; 8) severely limited and lie in bed all day, but can turn over by themselves; and 9) severely limited and lie in bed all day, and cannot turn over by themselves. Subjects who answered anywhere from items 3) to 9) at the starting point were excluded (n = 2952).
The number of person-years in the follow-up period was counted from the starting point (i.e., date of response to the third survey) to the date of death, emigration from Japan, or the end of the study period, whichever came first. For subjects who withdrew from the study or were lost to follow-up, the date of withdrawal or the last confirmed date of presence in the study was used as the date of censoring.
For group comparisons, hazard ratios (HR) and 95% confidence intervals (CI) were used to characterize the relative risk of all-cause mortality. To control for potential confounders, the Cox proportional hazards model was used. After setting physically inactive subjects as a reference category, the HR values of all-cause mortality were calculated for each physical activity group, adjusting for age and residential area (model 1). We then calculated the HR, adjusted for smoking, drinking, body mass index, diabetes history, and hypertension status (model 2), and then further adjusted for total MVPA volume (model 3). These analyses were repeated after setting the reference category as “0% VPA” to compare HR among physically active subjects.
In addition, analyses were further conducted separately by age group (<65 yr or ≥65 yr). To prevent confounding by occupational MVPA, we also conducted separate analyses among those not employed. On testing the proportional hazards assumption, we scaled Schoenfeld residuals and found no violation of proportionality. All analyses were conducted separately by sex. All statistical analyses were performed using STATA software (version 12); the level of significance was set at P < 0.05.
During the 894,718 person-years of follow-up (average follow-up period, 10.8 yr) for the 83,454 subjects, 8891 deaths were identified. The baseline characteristics of study subjects according to sex and physical activity are shown in Table 1. The mean ± SD age of participants was 61.5 ± 7.4 yr for men and 62.0 ± 7.6 yr for women.
Table 2 presents adjusted models showing associations between intensity of physical activity and all-cause mortality, stratified by age and sex. In the fully adjusted models, subjects engaging in any VPA showed significant associations with lower mortality. Subjects who meet physical activity guideline showed lower mortality than physically inactive subjects. The adjusted HRs for all-cause mortality were 0.75 (95% CI: 0.68–0.83), 0.73 (0.65–0.82), and 0.74 (0.62–0.89) among men, and 0.71 (0.62–0.81), 0.75 (0.64–0.88), and 0.74 (0.58–0.94) among women for “0% VPA,” “less than 30%,” and “30% or more”, respectively. In analyses setting the “0% VPA” group as the reference category, no statistically significant differences in mortality were observed for the “less than 30%” (men; 0.99 [95% CI: 0.87–1.13], and 1.01 [0.84–1.22], women: 1.03 [0.86–1.24]) and “30% or more VPA” groups (men; 1.01 [0.84–0.80], women: 1.04 [0.81–1.33]).
In analyses setting the “0% VPA” group as the reference category, no statistically significant differences in mortality were observed for the “less than 30%” (men: 0.99 [95% CI: 0.87–1.13], and 1.01 [0.84–1.22], women: 1.03 [0.86–1.24]) and “30% or more VPA” groups (men: 1.01 [0.84–0.80], women: 1.04 [0.81–1.33]).
In analyses restricted only to participants who were not employed, compared with physically inactive subjects, the adjusted HR values for all-cause mortality were 0.76 (95% CI: 0.64–0.91), 0.63 (0.52–0.78) and 0.74 (0.52–1.05) among men, and 0.60 (0.50–0.72), 0.65 (0.52–0.81) and 0.74 (0.54–1.00) among women for “0% VPA,” “30% or less,” and “more than 30%,” respectively.
In addition, to reduce the potential for spurious associations from reverse causation, we also repeated the analyses after excluding cases of early death (those occurring within 3 yr of the starting point). Neither of these sensitivity analyses had a substantial effect on the results.
The present study analyzed four groups of subjects categorized according to whether or not they met the physical activity guideline, and further categorized by the proportion of VPA to MVPA. Compared with physically inactive subjects, physically active subjects showed significantly reduced risks of all-cause mortality. Compared with those in “0% VPA” group, no statistically significant differences in mortality risks were observed among those in “less than 30%” and “30% or more” group. This finding suggests that meeting the physical activity guideline in either pattern is important for lowing mortality risk.
A few studies have examined the association between intensity of physical activity and health outcomes, and it remains controversial whether people could attain additional health benefit from VPA than MPA. In the Harvard Alumni Study, VPA showed an association with reduced risk of mortality compared with MPA among men (7,8). Shiroma et al. (10) showed that VPA led to additional reductions in all-cause mortality among men in the Harvard Alumni Study but not among women in the Women’s Health Study. In contrast, a recent Finnish study reported VPA to provide further health benefit between both sexes (9). In the Whitehall-II cohort study, MPA was associated with mortality but VPA was not (12). Our study provides additional information in an Asian population using gender-stratified analyses, which past studies have not sufficiently addressed (10).
Although several studies have investigated cause-specific associations, their findings are also inconsistent. In the Nurses’ Health Study, walking and VPA showed comparable benefits for reducing the risk of diabetes (17). In the Health Professionals’ Follow-up Survey, exercise intensity was associated with reduced risk independent of the number of MET-hours spent in physical activity (18). In a study of 1841 American adults, objectively measured VPA showed a stronger association than MPA with regard to lower prevalence of metabolic syndrome (19). The association between intensity of activity and health seems to vary in relation to health outcomes. The present study did not use cause-specific analysis because of the limited number of deaths, especially among women engaging in VPA. However, such analysis will be needed in future studies.
Although engaging in VPA was not shown to provide additional benefits in this study, some past studies have suggested further mortality risk reductions of VPA beyond MPA. Both MPA and VPA are able to lower the risk for coronary heart disease through increased energy expenditure and reduction of body fat (20,21). In addition, VPA could also provide unique health benefits such as enhancing cardiovascular fitness or metabolic improvement. Weston et al. (22) showed in their meta-analyses that VPA training could improve peak oxygen consumption, cardiac function, high-density lipoprotein level, blood pressure, and triglyceride levels in comparison with MPA training. VPA could decrease myocardial O2 demand and improve coronary blood flow and endothelial function, resulting in decreased risk of myocardial ischemia (23).
However, we did not observe that subjects who participated in VPA experienced lower risks, compared to those who did not engage in any VPA. The following explanations may account for these findings. First, compared to the study which showed VPA’s additional benefit (11), the subjects in this study were mainly middle-age or older people. Since they may have had associated health problems such as cardiovascular risks or deterioration of physical or cognitive functions, they may be vulnerable for engaging in VPA. For example, they may experience musculoskeletal injury through VPA. Second, the self-reported measure may have caused misclassification between MPA and VPA, consequently limiting our ability to detect true differences (24).
The strengths of our study are its prospective design and large sample size, enabling us to uncover the sex-specific effects of intensity-specific leisure-time physical activity on mortality. The response rate to the questionnaire (81%) was reasonably high and the loss to follow-up (0.3%) was negligible. There remain few prospective studies focusing on the longitudinal association between intensity of physical activity and mortality using data from an Asian population.
Nevertheless, some limitations of our study should be considered. First, the subjects categorized in the engaging VPA group were relatively few, especially among women; studies with a sufficient number of women engaging in VPA are thus needed to determine whether VPA provides health benefits to women. Second, occupational MVPA was not assessed in the present analysis. Because working men might have opportunity to engage in MVPA at work, a possibility of misclassification was assumed whereby men with occupational MVPA were less likely to engage in leisure-time MPA and/or VPA. Third, physical activity levels were assessed by self-report measures. The use of objective assessment for measuring MVPA would be more desirable in future studies (25). Fourth, changes in MVPA over time may also have caused misclassification. Fifth, although we measured and adjusted for possible confounding variables as far as possible, the possibility of unmeasured confounding variables cannot be totally disregarded. Moreover, some of the significant findings may have been due to chance.
Meeting the guidelines in either pattern of physical activity is important for lowering mortality risk. It may be suggested that people can receive comparable health benefit by MPA or VPA as long as they meet the guideline. Further studies with adequate sample sizes and investigating other health outcomes are needed to provide additional information.
The authors thank the study group members for their considerable effort in establishing and managing the Japan Public Health Center–based prospective study.
This study was supported by the National Cancer Center Research and Development Fund (23-A-31[toku] and 26-A-2) (since 2011) and a Grant-in-Aid for Cancer Research from the Ministry of Health, Labour and Welfare of Japan (from 1989 to 2010). Shigeru Inoue was supported by the Grant-in-Aid for Scientific Research (B) 16H03249 from the Japan Ministry of Education, Culture, Sports, Science and Technology. All authors have no other conflicts of interest, including related directorships, stock holdings, or contracts.
The authors declare that the results of the present study are presented clearly, honestly, and without fabrication, falsification, or inappropriate data manipulation. The present study does not constitute endorsement by American College of Sports Medicine.
1. Slattery ML, Jacobs DR Jr, Nichaman MZ. Leisure time physical activity
and coronary heart disease death. The US Railroad Study. Circulation
2. Lee IM, Shiroma EJ, Lobelo F, et al. Effect of physical inactivity on major non-communicable diseases worldwide: an analysis of burden of disease and life expectancy. Lancet
3. Centers for Disease Control and Prevention. Prevalence of leisure-time and occupational physical activity
among employed adults—United States, 1990. JAMA
4. Helmrich SP, Ragland DR, Paffenbarger RS Jr. Prevention of non–insulin-dependent diabetes mellitus with physical activity
. Med Sci Sports Exerc
5. Kohl HW 3rd, Craig CL, Lambert EV, et al. The pandemic of physical inactivity: global action for public health. Lancet
6. World Health Organization. Global Recommendations on Physical Activity
for Health. Geneva: World Health Organization; 2010. p. 7–8.
7. Lee IM, Hsieh CC, Paffenbarger RS Jr. Exercise intensity
and longevity in men. The Harvard Alumni Health Study. JAMA
8. Lee IM, Paffenbarger RS Jr. Associations of light, moderate, and vigorous intensity physical activity
with longevity. The Harvard Alumni Health Study. Am J Epidemiol
9. Lahti J, Holstila A, Lahelma E, Rahkonen O. Leisure-time physical activity
and all-cause mortality
. PLoS One
10. Shiroma EJ, Sesso HD, Moorthy MV, Buring JE, Lee IM. Do moderate-intensity
physical activities reduce mortality
rates to the same extent? J Am Heart Assoc
11. Gebel K, Ding D, Chey T, Stamatakis E, Brown WJ, Bauman AE. Effect of moderate to vigorous physical activity
on all-cause mortality
in middle-aged and older Australians. JAMA Intern Med
12. Sabia S, Dugravot A, Kivimaki M, Brunner E, Shipley MJ, Singh-Manoux A. Effect of intensity
and type of physical activity
: results from the Whitehall II cohort study. Am J Public Health
13. Haapanen N, Miilunpalo S, Vuori I, Oja P, Pasanen M. Characteristics of leisure time physical activity
associated with decreased risk of premature all-cause and cardiovascular disease mortality
in middle-aged men. Am J Epidemiol
15. Tsugane S, Sawada N. The JPHC study: design and some findings on the typical Japanese diet. Jpn J Clin Oncol
16. Haskell WL, Lee IM, Pate RR, et al. Physical activity
and public health: updated recommendation for adults from the American College of Sports Medicine and the American Heart Association. Circulation
17. Hu FB, Sigal RJ, Rich-Edwards JW, et al. Walking compared with vigorous physical activity
and risk of type 2 diabetes in women: a prospective study. JAMA
18. Tanasescu M, Leitzmann MF, Rimm EB, Willett WC, Stampfer MJ, Hu FB. Exercise type and intensity
in relation to coronary heart disease in men. JAMA
19. Janssen I, Ross R. Vigorous intensity physical activity
is related to the metabolic syndrome independent of the physical activity
dose. Int J Epidemiol
20. Williams PT. Health effects resulting from exercise versus those from body fat loss. Med Sci Sports Exerc
. 2001;33(6 Suppl):S611–21; discussion S40–1.
21. Rennie KL, McCarthy N, Yazdgerdi S, Marmot M, Brunner E. Association of the metabolic syndrome with both vigorous and moderate physical activity
. Int J Epidemiol
22. Weston KS, Wisloff U, Coombes JS. High-intensity
interval training in patients with lifestyle-induced cardiometabolic disease: a systematic review and meta-analysis. Br J Sports Med
23. Hambrecht R, Wolf A, Gielen S, et al. Effect of exercise on coronary endothelial function in patients with coronary artery disease. N Engl J Med
24. Dyrstad SM, Hansen BH, Holme IM, Anderssen SA. Comparison of self-reported versus accelerometer-measured physical activity
. Med Sci Sport Exerc
25. Lee I-M, Shiroma EJ. Using accelerometers to measure physical activity
in large-scale epidemiological studies: issues and challenges. Br J Sports Med