Skip to content

The bottom line: for better health be physically active at least is 2.5 hours of week. Note that HbA1c is a measure of glycated hemoglobin which identifies average plasma glucose concentration (and lower is better). From Medscape:

Exercise Tied to Cardiometabolic Markers in Clinic Patients 

Healthy, middle-aged outpatients who were physically active for at least 2.5 hours a week had better blood pressure and blood glucose levels than their sedentary peers in a large cross-sectional study in California. The differences were especially notable in women, in this study published online December 18, 2014 in Preventing Chronic Disease.

Men and women who were consistently physically active—defined as performing moderate to vigorous activity such as brisk walking for at least 150 minutes a week, as self-reported at all three outpatient visits in a 33-month period—had lower diastolic blood pressure, glucose, and HbA1c levels than patients not reporting exercise at that level.

Moreover, on a population level, the observed associations "were comparable to those needed to reduce the risk of coronary heart disease, stroke, and diabetes," they continue. "If healthcare providers would routinely assess the physical activity of their patients and refer those who are physically inactive to effective physical-activity programs, it may reduce the burden of future chronic diseases."

They analyzed electronic records from over 622,000 adults covered by Kaiser Permanente Southern California healthcare insurance who made at least three clinic visits between April 2010 and December 2012 and were not being treated for diabetes or hypertension.

The consistently active women had systolic and diastolic blood pressures that were 4.60-mm-Hg lower and 3.28-mm-Hg lower, respectively, than inactive women. Perhaps surprisingly, somewhat active women had slightly better blood-pressure values than the more active group.

Interesting term "actively sedentary", which may describe many of us. From Medscape:

Walking Is the Superfood of Fitness, Experts Say

NEW YORK (Reuters) - Walking may never become as trendy as CrossFit, as sexy as mud runs or as ego-boosting as Ironman races but for fitness experts who stress daily movement over workouts and an active lifestyle over weekends of warrior games, walking is a super star.

For author and scientist Katy Bowman, walking is a biological imperative like eating. In her book, "Move Your DNA: Restore Your Health Through Natural Movement," she suggests there are movement nutrients, just like dietary nutrients, that the body needs. "Walking is a superfood. It's the defining movement of a human," said Bowman, a biomechanist based in Ventura, California. 

Researchers say emerging evidence suggests that combined physical activity and inactivity may be more important for chronic disease risk than physical activity alone. "Actively sedentary is a new category of people who are fit for one hour but sitting around the rest of the day," Bowman said. "You can't offset 10 hours of stillness with one hour of exercise."

She added that a small study of non-obese men published in the journal Medicine & Science in Sports and Exercise by scientists at Indiana University suggests that three five-minute walks done throughout three hours of prolonged sitting reverses the harmful effects of prolonged sitting on arteries in the legs.

Three miles (5 kilometers) per hour is a good beginning, gradually working to 4 miles per hour, she said about walking.

Two related stories that look at children, exercise, and academic performance. Boys, in general, have higher activity levels than girls, and they need exercise and recess to be able to get through the rest of the school day. Sitting quietly in class and doing classwork is hard when one has lots of excess energy. In fact, sitting still for hours on end is NOT healthy in any way for anyone! Fidget, fidget, fidget... From Science Daily:

High levels of physical activity linked to better academic performance in boys

Higher levels of physical activity are related to better academic achievement during the first three school years, particularly in boys, research shows. For instance, boys with higher levels of physical activity, and especially walking and bicycling to and from school, had better reading skills than less active boys....The findings of the present study highlight the potential of physical activity during recess and participation in organized sports in the improvement of academic achievement in children

 Instead of medicine, why aren't doctors prescibing exercise? From The Atlantic:

Exercise Is ADHD Medication

Physical movement improves mental focus, memory, and cognitive flexibility; new research shows just how critical it is to academic performance.

...More insipid but also more clearly critical to addressing what's being called the ADHD epidemic is plain old physical activity.

This morning the medical journal Pediatrics published research that found kids who took part in a regular physical activity program showed important enhancement of cognitive performance and brain function. The findings, according to University of Illinois professor Charles Hillman and colleagues, "demonstrate a causal effect of a physical program on executive control, and provide support for physical activity for improving childhood cognition and brain health." If it seems odd that this is something that still needs support, that's because it is odd, yes. Physical activity is clearly a high, high-yield investment for all kids, but especially those attentive or hyperactive. This brand of research is still published and written about as though it were a novel finding, in part because exercise programs for kids remain underfunded and underprioritized in many school curricula, even though exercise is clearly integral to maximizing the utility of time spent in class.

Earlier this month, another study found that a 12-week exercise program improved math and reading test scores in all kids, but especially in those with signs of ADHD.

Last year a very similar study in the Journal of Attention Disorders found that just 26 minutes of daily physical activity for eight weeks significantly allayed ADHD symptoms in grade-school kids. The modest conclusion of the study was that "physical activity shows promise for addressing ADHD symptoms in young children." 

"If physical activity is established as an effective intervention for ADHD," they continued, "it will also be important to address possible complementary effects of physical activity and existing treatment strategies ..." Which is a kind of phenomenal degree of reservation compared to the haste with which millions of kids have been introduced to amphetamines and other stimulants to address said ADHD. The number of prescriptions increased from 34.8 to 48.4 million between 2007 and 2011 alone. The pharmaceutical market around the disorder has grown to several billion dollars in recent years while school exercise initiatives have enjoyed no such spoils of entrepreneurialism. 

Over all, the pandemic of physical inactivity, as Hillman and colleagues put it in their Pediatrics journal article today, is "a serious threat to global health" responsible for around 10 percent of premature deaths from noncommincable diseases. 

John Ratey, an associate professor of psychiatry at Harvard, suggests that people think of exercise as medication for ADHD. Even very light physical activity improves mood and cognitive performance by triggering the brain to release dopamine and serotonin, similar to the way that stimulant medications like Adderall do

Well DUH ! Of course children need to run, run, run or somehow exercise to get rid of excess energy. That's why recess is so important (but unfortunately so many schools are eliminating it). It is incredibly hard for children to quietly sit for many, many hours straight like little robots working tirelessly on schoolwork, especially those with high energy levels to start with. From Medscape:

Before-School Exercise May Reduce ADHD Symptoms

Moderate to vigorous aerobic exercise in the morning may reduce symptoms of attention-deficit/hyperactivity disorder (ADHD) in young children at risk for the illness, new research suggests.

A randomized study of 202 kindergarteners, 1st graders, and 2nd graders showed that those who completed 12 weeks of before-school physical activity had significantly higher reductions in inattention and moodiness than those who completed a sedentary classroom-based intervention.In addition, the subgroup of children with elevated ADHD symptoms who went through the before-school exercise program showed reduced impairment associated with ADHD risk in both their school and home settings.

"We need more studies to replicate the results, but I think the take-home message is that aerobic exercise is a health-producing activity ― and there are really no negative side effects from it," added Dr. Hoza.

Past research has shown some positive effects from exercise on patients with ADHD, providing evidence that it may be "a viable strategy for improving symptoms, behavior, achievement, inhibitory control, and neurocognitive function in youth with elevated ADHD symptoms," write the investigators.

In the current study, the researchers enrolled 94 children at risk for ADHD and 108 children deemed "typically developing" to act as their control group....The physical activity involved continuous movement requiring children to breathe hard and included a variety of age-appropriate activities and games.

"Although our findings indicated that all participants showed improvements, children with ADHD risk receiving exercise benefited across a broader range of outcomes than those receiving the sedentary activities," said coinvestigator Alan Smith, PhD, chair of the Department of Kinesiology at Michigan State University in East Lansing, in a release.

Several more articles on the benefits of exercise. From Science Daily:

Train your heart to protect your mind

Exercising to improve our cardiovascular strength may protect us from cognitive impairment as we age, according to a new study. "Our body's arteries stiffen with age, and the vessel hardening is believed to begin in the aorta, the main vessel coming out of the heart, before reaching the brain. Indeed, the hardening may contribute to cognitive changes that occur during a similar time frame," explained the first author of the study. "We found that older adults whose aortas were in a better condition and who had greater aerobic fitness performed better on a cognitive test. We therefore think that the preservation of vessel elasticity may be one of the mechanisms that enables exercise to slow cognitive aging."

The researchers worked with 31 young people between the ages of 18 and 30 and 54 older participants aged between 55 and 75. This enabled the team to compare the older participants within their peer group and against the younger group who obviously have not begun the aging processes in question. None of the participants had physical or mental health issues that might influence the study outcome.

The results demonstrated age-related declines in executive function, aortic elasticity and cardiorespiratory fitness, a link between vascular health and brain function, and a positive association between aerobic fitness and brain function. "Although the impact of fitness on cerebral vasculature may however involve other, more complex mechanisms, overall these results support the hypothesis that lifestyle helps maintain the elasticity of arteries, thereby preventing downstream cerebrovascular damage and resulting in preserved cognitive abilities in later life."

From Science Daily:

Physically fit kids have beefier brain white matter than their less-fit peers

A new study of 9- and 10-year-olds finds that those who are more aerobically fit have more fibrous and compact white-matter tracts in the brain than their peers who are less fit. 'White matter' describes the bundles of axons that carry nerve signals from one brain region to another. More compact white matter is associated with faster and more efficient nerve activity.

The analysis revealed significant fitness-related differences in the integrity of several white-matter tracts in the brain: the corpus callosum, which connects the brain's left and right hemispheres; the superior longitudinal fasciculus, a pair of structures that connect the frontal and parietal lobes; and the superior corona radiata, which connect the cerebral cortex to the brain stem."All of these tracts have been found to play a role in attention and memory," Chaddock-Heyman said. 

From Science Daily:

Exercise may protect older women from irregular heartbeat

Increasing the amount or intensity of physical activity can cut the chances of older women developing a life-threatening irregular heartbeat, according to new research. Researchers found that post-menopausal women who were the most physically active had a 10 percent lower risk of developing atrial fibrillation (AF), compared to women with low levels of physical activity, even if they were obese. Obesity is an important risk factor for atrial fibrillation.

This is Part 2 on how lifestyle influences aging. Many recent research reports tell of a link between our lifestyle and how we'll age - whether we'll be active and healthy well into our 80s or in terrible shape and dying young. Mind you, these are not "definites" because nothing can give you a guarantee, but they are ways we can improve our odds in living the long and healthy life that we want. From February 2014 Medscape:

Cancers Caused by Lifestyle Behaviors: Experts Urge Action

In launching the World Cancer Report 2014 earlier this week, the editors emphasized the need for prevention and highlighted lifestyle behaviors that lead to cancer, including smoking tobacco, drinking alcohol, overweight/obesity, and lack of exerciseThe report, issued by the International Agency for Research on Cancer (IACR), contains contributions from more than 250 scientists worldwide, many of them leading experts in their fields. 

In the United States, 1 in 3 cancer deaths is related to obesity, poor nutrition, or physical inactivity, and the problem will only increase as more countries and regions adopt the diet and lifestyles of more economically developed economies."

Tobacco, both smoked and smokeless, remains the world's leading cause of cancer morbidity and mortality, the report notes. The IACR and also the US Surgeon General have concluded that the relationship with smoking is causal for cancers of the nasal and oral cavities, hypopharynx, larynx, trachea, esophagus, lung, bronchus, bone marrow (leukemia), stomach, kidney, pancreas, ureter, uterus, bladder, and cervix. The IACR expands this list to also include paranasal sinuses, liver, colon, rectum, and ovary (mucinous), but says it is unclear if there is a link with breast cancer.

Still under-recognized, and not acted on, is the association between drinking alcohol and cancer. The agency says cancers caused by drinking alcoholic beverages include those of the oral cavity, pharynx, larynx, esophagus, liver, colorectum, and female breast.

Excess body fat increases the risk for cancers of the esophagus, colon, pancreas, endometrium, and kidney, as well as postmenopausal breast cancer. The evidence for obesity increasing the risk for these cancers is "convincing," the agency comments, and there is a dose–response relationship, so being overweight is less risky than being obese.

Regular physical activity reduces the risk for multiple cancers by contributing to weight control, and also reduces the risk for colorectal and breast cancer by additional mechanisms. The general consensus among researchers is that exercise should be of moderate intensity and average at least an hour each day.

High consumption of red meat, especially processed meat, is associated with a risk for colorectal cancer. "A diet high in fruit and vegetables and whole grains does not appear to be as strongly protective against cancer as initially believed," the report notes. "However, this dietary pattern is still advisable because of the benefits for diabetes and cardiovascular diseases, and some possible reductions in cancer incidence."

From Science Daily:

Watching too much TV may increase risk of early death: Three hours a day linked to premature death from any cause

Adults who watch TV three hours or more a day may double their risk of premature death from any cause. Researchers suggest adults should consider getting regular exercise, avoiding long sedentary periods and reducing TV viewing to one to two hours a day.

Results of a large study published in the Mayo Clinic Proceedings. From Science Daily:

Large waist linked to poor health, even among those in healthy body mass index ranges

Having a big belly has consequences beyond trouble squeezing into your pants. It’s detrimental to your health, even if you have a healthy body mass index (BMI), a new international collaborative study has found. Men and women with large waist circumferences were more likely to die younger, and were more likely to die from illnesses such as heart disease, respiratory problems, and cancer after accounting for body mass index, smoking, alcohol use and physical activity.

Some good news for those who have to sit for long periods every day at work - being physically fit may help. From Science Daily:

Physical fitness associated with less pronounced effect of sedentary behavior

Physical fitness may buffer some of the adverse health effects of too much sitting, according to a new study. Sedentary behavior has been linked to an increase risk of obesity, metabolic syndrome, type 2 diabetes mellitus, cardiovascular disease, some cancers, and premature death. But previous studies of the association have not taken into account the protective impact of fitness, a strong predictor of cardiovascular disease incidence and mortality.

It seems that research showing benefits of exercise is multiplying. This study only looked at men, and if you look at the "after age 40 group", their average age of starting endurance training was 48. From Science Daily:

Forty not too old or too late to start endurance training

A study of healthy senior men has found that "relatively intensive" endurance exercise confers benefits on the heart irrespective of the age at which they began training. The benefits were evident and comparable in those who had started training before the age of 30 or after the age of 40. As a result, said the investigators, 40 is not too old to start endurance training.

The study was performed in 40 healthy men (without cardiovascular risk factors) aged between 55 and 70 years who were divided for assessment according to the level of exercise they took and the ages at which they began. Thus, 10 of the men had never exercised for more than 2 hours a week throughout their lives, and 30 had exercised for at least 7 hours a week for over five years.

The regular exercise they took was either running or cycling. Those beginning before the age of 30 had been training for an average of 39 years (since the age of 22) and those starting at 40 for 18 years (since the age of 48).

First, resting heart rate was found to be similar between the two exercise groups (T30 56.8 bpm, T40 58.1 bpm), but significantly faster in the non-exercising men (69.7 bpm). Maximal oxygen uptake was also similar between the T30 (47.3 ml/min/kg) and T40 groups (44.6 ml/min/kg), but significantly lower in the non-exercising men (33.0 ml/min/kg).

The study also found no difference between T30 and T40 in cardiac echocardiography tests. "Thus," said Matelot, "despite biological changes with age, the heart still seems -- even at the age of 40 -- amenable to modification by endurance training. Starting at the age of 40 does not seem to impair the cardiac benefits.

Matelot pointed out that aging is associated with adverse structural and functional changes to the cardiovascular system. And, while physical activity is unable to prevent these changes, it is able to slow them down.

More studies on the amazing benefits of exercise, or activity, even light activity.  From Science Daily:

Simple tests of physical capability in midlife linked with survival

Low levels of physical capability (in particular weak grip strength, slow chair rise speed and poor standing balance performance) in midlife can indicate poorer chances of survival over the next 13 years, while greater time spent in light intensity physical activity each day is linked to a reduced risk of developing disability in adults with or at risk of developing knee osteoarthritis, suggest two papers published on today.

The researchers conclude that there are "robust associations of standing balance time, chair rise speed and grip strength at age 53 with all-cause mortality rates over 13 years of follow-up." They suggest there is value in using these simple tests to assess physical capability in midlife to identify those people who are less likely to achieve a "long and healthy life."

In a linked paper, a team of US researchers set out to investigate whether time spent in light intensity physical activity is related to a reduced risk of developing disability and disability progression.

Their study involved 1,680 men and women aged 49-83 years free of disability, but with or at high risk for developing knee osteoarthritis, a major disability risk factor. The primary outcome was the development of disability at a two-year follow up visit. In total, participants averaged 245 minutes/day of non-sedentary activity, of which the vast majority was light intensity activities (229 minutes/day).

The results show a "significant and consistent relationship between greater time spent in light intensity activity and a reduced risk of developing disability or progression in disability," say the authors.

More details on the second study. From Science Daily:

Light activity every day keeps disability at bay

Another study discussing how physical activity reduces the risk of breast cancer for women of all ages and sizes. From Science Daily:

Regular physical activity reduces breast cancer risk irrespective of age

Practicing sport for more than an hour day reduces the risk of contracting breast cancer, and this applies to women of any age and any weight, and also unaffected by geographical location, according to research presented to the 9th European Breast Cancer Conference (EBCC-9). Compared with the least active women, those with the highest level of physical activity reduced their risk of breast cancer by 12%, researchers say.

Professor Mathieu Boniol, Research Director at the International Prevention Research Institute, Lyon, France, recently reported the results of a meta-analysis of 37 studies published between 1987 and 2013, representing over four million women. "These are all the studies looking at the relationship between physical exercise and breast cancer risk that have been published to date, so we are confident that the results of our analysis are robust," he said.

Although the results varied according to tumour type, the overall message was encouraging, the researchers say. However, in women taking hormone replacement therapy (HRT), the protective effect of exercise seemed to be cancelled out. But increased awareness of the side effects of HRT means that its use is decreasing in a number of countries, and this means that the beneficial effects of activity will most likely grow in the years to come. 

Physical activity is known to have a protective role in other cancers, as well as in disorders such as cardiovascular disease. Although the mechanisms for its effect are unclear, the results are largely independent of body mass index (BMI), so the effect must be due to more than weight control. And the age at which sporting activity starts also appears to be immaterial; the researchers found no indication that breast cancer risk would decrease only when physical activity started at a young age.

"Adding breast cancer, including its aggressive types, to the list of diseases that can be prevented by physical activity should encourage the development of cities that foster sport by becoming bike and walk-friendly, the creation of new sports facilities, and the promotion of exercise through education campaigns," said Prof Boniol. 

It appears most of us sit too much. From Science Daily:

Obese Americans get less than one minute of vigorous activity per day, research shows

Researchers at the University of South Carolina’s Arnold School of Public Health have validated a new method for calculating physical activity, sedentary behavior, and the food energy requirements of Americans. The results suggest that as a nation, we spend more than 15 hours per day sleeping and sitting, and that obese men and women spend less than one minute per day in vigorous activity.

The study of the Physical Activity Ratio (PAR) protocol is significant because it provides the first nationally representative estimates of total daily energy expenditure, physical activity and sedentary behavior for the U.S. population.

Data sets for the study were obtained from the National Health and Nutrition Examination Survey 2005-2006, a complex sample of the U.S. population conducted by the Centers for Disease Control and Prevention, and included adults age 20 to 74. The sample population was then divided into three Body Mass Index (BMI) categories: normal weight (18-25 kg/m2), overweight (25-29.9 kg/m2) and obese (30 kg/m2 or more) and took into account all factors contributing to energy expenditure, including sleep, and the digestion and metabolism of food.

The study found that the 1,272 men and 1,325 women that comprised the final sample exhibited key differences based on sex and BMI. Men were taller, heavier, and had greater resting energy expenditure than women. Men also spent more hours per day engaging in moderate and vigorous physical activity, and reported less sleep.

Not surprisingly, obese men and women were significantly less physically active and spent more time in sedentary behaviors than their normal weight counterparts. Obese men and women also reported less sleep and spent almost no time in more intense forms of physical activity. “Given that physical inactivity is now a leading cause of death and disability in the world, these data are essential in advancing the science of obesity and health,” Archer said.