Sitting Time and Obesity in Men Living in the United States

More Sitting Time for Men – More Likely to Be Obese

Background: The Center of Disease Control and Prevention (CDC) reported in November 2016 that over one-third (35%) of adults in the United States are obese. Obesity is typically defined by Body Mass Index (abbreviated BMI). BMI is calculated by weight in kilograms divided by the square of height in meters. You can ask your health care provider to calculate your BMI at your next appointment. A value between 25 and 30 means someone is overweight. A BMI value of 30 or higher indicates obesity.

Study: Dr. Carolyn Barlow and colleagues at the Cooper Institute in Dallas, Texas,  reported the results of a study which analyzed sitting time and body weight.  The study was published in December 29, 2016, issue of the journal Prevention of Chronic Diseases.  doi: 10.5888/pcd13.160263.

Results: Estimates of sitting time, measures of obesity, blood lipids, blood glucose, blood pressure, and exercise testing were collected in 4,486 men and 1,845 women. Nearly one-half of the men reported sitting three-fourths of the day, while only 13% of women said the same.

Men who sat almost all of the time were more likely to be obese as measured by waist size (circumference) or body fat compared with men who sat almost none of the time. Sitting time was NOT associated with other cardiac risk factors. For women, there was no significant association between sitting time and cardiac risk factors.

Conclusions: The researchers could not pinpoint a cause for the higher rates of obesity in sedentary men. Dr. Barlow said that one limitation of the study was that subjects were mainly white, generally healthy, and well educated. The authors suggested that reducing sitting time can be a first step in a plan for men to be more active.

Woman working at desk reduces sitting time

Woman working at stand up desk

My Comments:  In a previous study from the Cooper Institute (Mayo Clinic Proceeding, September 29, 2015), researchers showed that standing for at least one-quarter of the day was linked to a lower risk of obesity. For example, standing a quarter of the time was linked to a reduced chance of obesity (by 32% in men and by 35% in women) . If you sit at desk for work or for using a computer, consider getting a stand up desk with adjustable height that allows you to stand.

Obesity and Shortness of Breath in COPD

Benefit of Mild to Moderate Obesity in those with COPD

Dennis Jensen, Ph.D., Assistant Professor at McGill University, presented information on the benefit of obesity on shortness of breath in those with COPD at the CHEST Annual Meeting held October 24-28, 2015, in Montreal, Quebec, Canada.

Dennis Jensen, Ph.D., Assistant Professor at McGill University in Montreal

Dennis Jensen, Ph.D., Assistant Professor at McGill University in Montreal

First, Dr. Jensen reviewed how obesity is defined. The most widely used method is called the BMI (body mass index) which is the ratio of weight squared to height using the metric system. Studies show that 54% of the general adult population in the United States and Canada are considered obese based on a BMI of 30 or higher.

In general, studies show that obese individuals who have COPD are less active, are hospitalized more, and require more home care compared to those with COPD and are normal weight.

Paradoxes    

However, there are a few paradoxes when other outcomes are considered. For example, obese individuals with COPD:

  1. have a lower all cause mortality compared with those with COPD of normal weight
  2. can exercise to a higher level (intensity) on a stationary cycle compared with non-obese COPD individuals.
  3. report lower ratings of breathlessness (dyspnea) for the same level of breathing (ventilation) while exercising on the cycle than those with COPD of normal weight

Why? 

Extra weight on the chest limits the lungs from over-expanding (called hyperinflation) at rest and during exercise. Hyperinflation occurs in most individuals who have COPD and is a major cause of shortness of breath.

X-ray of the chest showing too much air in the lungs (hyperinflation) and the diaphragm muscle is pushed down.

X-ray of the chest showing too much air in the lungs (hyperinflation). This pushes the diaphragm muscle down and makes it less effective.

 

When the extra weight is around the chest (called central obesity- think of an apple and not a pear), not as much hyperinflation takes place with daily activities. This makes it a little easier to breathe.

My Comment

The information that Dr. Jensen presented led to an interesting discussion, particularly about what happens when someone who is overweight and has COPD loses weight. Is that good or bad for breathing? Dr. Jensen commented that there are no studies that have addressed this.

Dr. Denis O'Donnell, Professor of Medicine at Queen's University, in Kingston, Ontario, Canada

Dr. Denis O’Donnell, Professor of Medicine at Queen’s University, in Kingston, Ontario, Canada

Dr. Denis O’Donnell, another presenter at the session, commented that the benefit of obesity occurs in those with mild to moderate obesity (about 20-30 pounds of extra body weight). Extreme, or morbid, obesity causes more breathing difficulty along with other medical problems.

What’s New About Breathlessness

Dr. Denis O’Donnell (Kingston, Ontario, Canada) and I wrote a review called Recent Advances in Dyspnea (medical word for breathlessness) in the January 2015 issue of the journal CHEST (pages 232-241). The review covered new research information about breathing difficulty over the past 4 years.

Here is information about how breathlessness affects daily life.

Dr. Denis O'Donnell, Professor of Medicine at Queen's University, in Kingston, Ontario, Canada

Dr. Denis O’Donnell, Professor of Medicine at Queen’s University, in Kingston, Ontario,

  1. Of 2,258 individuals with severe COPD, breathlessness was worse upon awakening in the morning.
  2. Most individuals reported that their breathing varied from day to day and from week to week.
  3. Treatment with a long-acting bronchodilator reduced the variability in breathing difficulty.
  4. Women generally report more breathlessness than men.
  5. In the United Kingdom, 20% of menopausal women reported breathing difficulty. This may be related to low levels of estrogen and progesterone which could affect mood.
  6. Obesity is associated with an increase in breathlessness.
  7. Anxiety and depression are more common in those with heart and lung diseases.

Here are some of the key findings about treatment.

  1. Most long-acting bronchodilators inhaled once or twice daily improve breathing difficulty in those with COPD.
  2. In general. the improvement in breathlessness is greater with two different bronchodilators in a single inhaler compared with one bronchodilator in an inhaler.
  3. Individuals with COPD reported less breathlessness related to anxiety after 8 weeks in a pulmonary rehabilitation program compared with “usual care.”

Here is information on new therapies not yet approved to relieve breathing difficulty. These therapies require more testing before use.

  1. Those with COPD had less breathlessness after acupuncture compared with a sham, or pretend, treatment.
  2. Placement of valves or coils into breathing tubes through a scope can deflate the lung and improve breathing difficulty.
  3. Using a breathing machine connected to plastic tubes in the nose (nasal cannula) to assist breathing during walking improves breathing by allowing the breathing muscles to work less.