Human physical activities differ significantly from other species. How, when and why did these capabilities evolve? What adaptations underlie them? And how did the evolution of human physical activity affect other key human characteristics that have advanced our species?
Herman Pontzer explores the evolution of human metabolism and its role in our evolution and health. From an evolutionary perspective, life is a game of turning energy into offspring. The strategies that species use to acquire energy, in the form of food, and allocate energy to the essential tasks of growth, maintenance, movement, and reproduction, are incredibly diverse and reflect the ecological pressures and opportunities encountered. There is a deep evolutionary history of the human metabolic strategy and our divergence from other apes.
Timeline: 00:00 – Start 01:38 – The Evolution of Human Metabolism
In this cross-sectional study of 5364 couples consisting of employees and spouses (or domestic partners) undergoing an annual employer-sponsored health assessment, 79% of the couples were in the nonideal category of a CV health score. This within-couple concordance of nonideal CV health scores was associated mostly with unhealthy diet and inadequate physical activity.
The study included 10 728 participants (5364 couples): 7% were African American, 11% Hispanic, 21% Asian, and 54% White (median [interquartile range] age, 50 [41-57] years for men and 47 [39-55] for women). For most couples, both members were in the ideal category or both were in a nonideal category.
Concordance ranged from 53% (95% CI, 52%-54%) for cholesterol to 95% (95% CI, 94%-95%) for diet. For the CV health score, in 79% (95% CI, 78%-80%) of couples both members were in a nonideal category, which was associated mainly with unhealthy diet (94% [95% CI, 93%-94%] of couples) and inadequate exercise (53% [95% CI, 52%-55%] of couples). However, in most couples, both members were in the ideal category for smoking status (60% [95% CI, 59%-61%] of couples) and glucose (56% [95% CI, 55%-58%]).
Except for total cholesterol, when 1 member of a couple was in the ideal category, the other member was likely also to be in the ideal category: the adjusted odds ratios for also being in the ideal category ranged from 1.3 (95% CI, 1.1-1.5; P ≤ .001) for blood pressure to 10.6 (95% CI, 7.4-15.3; P ≤ .001) for diet. Concordance differed by ethnicity, socioeconomic status, and geographic location.
LOS ANGELES — Modifying 12 risk factors over a lifetime could delay or prevent 40% of dementia cases, according to an updated report by the Lancet Commission on dementia prevention, intervention and care presented at the Alzheimer’s Association International Conference (AAIC 2020).
Twenty-eight world-leading dementia experts added three new risk factors in the new report — excessive alcohol intake and head injury in mid-life and air pollution in later life. These are in addition to nine factors previously identified by the commission in 2017: less education early in life; mid-life hearing loss, hypertension and obesity; and smoking, depression, social isolation, physical inactivity and diabetes later in life (65 and up).
Schneider and commission members recommend that policymakers and individuals adopt the following interventions:
Aim to maintain systolic blood pressure of 130 mm Hg or less from the age of 40.
Encourage use of hearing aids for hearing loss and reduce hearing loss by protecting ears from high noise levels.
Reduce exposure to air pollution and second-hand tobacco smoke.
Prevent head injury (particularly by targeting high-risk occupations).
Limit alcohol intake to no more than 21 units per week (one unit of alcohol equals 10 ml or 8 g pure alcohol).
Stop smoking and support others to stop smoking.
Provide all children with primary and secondary education.
Lead an active life into mid-life and possibly later life.
Reduce obesity and the linked condition of diabetes.
From The Lancet Diabetes & Endocrinology (June 2020):
Our findings show that the intensive lifestyle intervention led to significant weight loss at 12 months, and was associated with diabetes remission in over 60% of participants and normoglycaemia in over 30% of participants. The provision of this lifestyle intervention could allow a large proportion of young individuals with early diabetes to achieve improvements in key cardiometabolic outcomes, with potential long-term benefits for health and wellbeing.
Type 2 diabetes is affecting people at an increasingly younger age, particularly in the Middle East and in north Africa. We aimed to assess whether an intensive lifestyle intervention would lead to significant weight loss and improved glycaemia in young individuals with early diabetes.
Between July 16, 2017, and Sept 30, 2018, we enrolled and randomly assigned 158 participants (n=79 in each group) to the study. 147 participants (70 in the intervention group and 77 in the control group) were included in the final intention-to-treat analysis population. Between baseline and 12 months, the mean bodyweight of participants in the intervention group reduced by 11·98 kg (95% CI 9·72 to 14·23) compared with 3·98 kg (2·78 to 5·18) in the control group (adjusted mean difference −6·08 kg [95% CI −8·37 to −3·79], p<0·0001). In the intervention group, 21% of participants achieved more than 15% weight loss between baseline and 12 months compared with 1% of participants in the control group (p<0·0001). Diabetes remission occurred in 61% of participants in the intervention group compared with 12% of those in the control group (odds ratio [OR] 12·03 [95% CI 5·17 to 28·03], p<0·0001). 33% of participants in the intervention group had normoglycaemia compared with 4% of participants in the control group (OR 12·07 [3·43 to 42·45], p<0·0001).
From a March 5, 2020 American Academy of Neurology release:
“These results are exciting, as they suggest that people may potentially prevent brain shrinking and the effects of aging on the brain simply by becoming more active,” said study author Yian Gu, Ph.D., of Columbia University in New York and a member of the American Academy of Neurology.
“Recent studies have shown that as people age, physical activity may reduce the risk of cognitive decline and dementia. Our study used brain scans to measure the brain volumes of a diverse group of people and found that those who engaged in the top third highest level of physical activity had a brain volume the equivalent of four years younger in brain aging than people who were at the bottom third activity level.”
Older people who regularly walk, garden, swim or dance may have bigger brains than their inactive peers, according to a preliminary study to be presented at the American Academy of Neurology’s 72nd Annual Meeting in Toronto, Canada, April 25 to May 1, 2020. The effect of exercise was equal to four fewer years of brain aging. The study used magnetic resonance imaging (MRI) scans to measure the brains of people with a range of activity levels, including those who were inactive to those who were very active. The scans showed less active people had smaller brain volume.
We derived a healthy lifestyle score based on information on five lifestyle factors—diet, smoking, physical activity, alcohol consumption, and body mass index (BMI).
Our findings suggest that promotion of a healthy lifestyle would help to reduce the healthcare burdens through lowering the risk of developing multiple chronic diseases, including cancer, cardiovascular disease, and diabetes, and extending disease-free life expectancy. Public policies for improving food and the physical environment conducive to adopting a healthy diet and lifestyle, as well as relevant policies and regulations (for example, smoking ban in public places or trans-fat restrictions), are critical to improving life expectancy, especially life expectancy free of major chronic diseases.
The average life expectancy in the world has increased substantially in the past few decades. The aging of the population has led to a high prevalence of chronic diseases such as diabetes, cardiovascular disease, and cancer. Although people live longer, older individuals often live with disabilities and chronic diseases. People with chronic diseases including cancer, cardiovascular disease, and diabetes have a shorter life expectancy than do their peers without these chronic conditions. Estimates of the loss in life years due to these chronic conditions range from 7.5 to 20 years, depending on the methods used and the characteristics of the study population.
Modifiable lifestyle factors including smoking, physical activity, alcohol intake, body weight, and diet quality affect both total life expectancy and incidence of chronic diseases. Studies have shown that smoking, inactivity, poor diet quality, and heavy alcohol consumption contribute up to 60% of premature deaths and 7.4-17.9 years’ loss in life expectancy. Nevertheless, little research has looked at how a combination of multiple lifestyle factors may relate to life expectancy free from the major diseases of diabetes, cardiovascular disease, and cancer.
At the moment, about two-thirds of Americans do not meet the standard exercise guidelines of about 30 minutes a day of moderate exercise, such as walking.
These findings might suggest that, if we adjusted our schedules and turned off the TV, phone or computer, most of us would have plenty of time to work out.
Almost all of the respondents — whatever their income, age, gender or ethnicity — reported about five hours a day of leisure time. Men tended to have more free time than women, older people more than the young, and African-American women the least of all. But no group reported less than about four and a half hours a day of free time.