New studies value of exercise over weight loss for heart disease patients; Vitamin D linked to reduced risk 05/21/2018
Sadly, even vigorous, regular exercise doesn’t necessarily yield weight loss.
That’s particularly true for older adults, whose metabolisms have begun to slow down.
In fact, it’s entirely possible to work out daily without shedding many pounds — unless you also change your diet.
Whole-food diets and sharp cuts in starches, sugars, and omega-6 fatty acids appear particularly effective.
For more on that, see Stunning Study Upsets a Big Diet Debate, Omega-6 Fats Drive Obesity; Omega-3s Help Avoid It, Does Colorful Produce Cut Pounds?, and research reports in the Weight & Fitness section of our news archive.
Now, the results of one new study elevate exercise well above weight loss when it comes to reducing the risk for heart disease — and death or disability related to it.
And the findings from a second study undermine the so-called “obesity paradox” seen in many population studies — in which heart patients with excess weight appeared to enjoy better prognoses and longer lifespans than their leaner counterparts.
Before delving into the details of the two new studies, this is what’s meant by “overweight” and “obese”:
- Obesity is defined as a body mass index (BMI) of 30 to 39.9.
- Overweight is defined as a body mass index (BMI) 25 to 29.9.
To survive heart disease, exercise beats out weight loss
The first study was conducted by scientists from universities in Norway, Louisiana, and Australia (Moholdt T et al. 2018).
Their epidemiological study among heart patients linked exercise to healthier, longer lives, while weight loss wasn’t beneficial and could be harmful to people of normal weight.
The international study included 3,307 people (1,038 women) diagnosed with coronary heart disease following either a heart attack or an episode of angina (severe chest pain due to lack of blood supply to the heart). On average, the patients were followed for 15 years, during which time nearly half (1,493) died.
The patients who engaged in 150 minutes of moderate exercise a week dropped their risk of death by 19% — while those who exercised more enjoyed a 36% reduction in death risk.
In contrast, weight loss was linked to a 36% rise in death risk among participants of normal weight — while weight gain wasn’t associated with such an increase.
In addition, even if the regular exercisers scaled back on their amount of weekly exercise, they continued to enjoy a lower risk of death, compared with overweight adults who were basically sedentary.
While the results need to be replicated, they suggest that a regular, moderate fitness routine goes a long way to protect heart patients from premature death.
The Centers for Disease Control and Prevention (CDC) currently recommends 2 hours and 30 minutes (150 minutes) of moderate-intensity aerobic activity every week, or 1 hour and 15 minutes (75 minutes) of vigorous aerobic activity.
For greater health benefits, the CDC recommends 5 hours of moderate-intensity aerobic activity every week, or 2 hours and 30 minutes (150 minutes) of vigorous-intensity aerobic activity.
Examples of moderate workouts include:
• Water aerobics
• Doubles tennis
• Mowing the lawn
• Bicycling slower than 10 miles per hour
• Walking briskly (3 miles per hour or faster)
• Cleaning (washing windows, vacuuming, mopping)
If vigorous workouts are more your speed, these are some examples:
• Brisk hiking
• Jumping rope
• Singles tennis
• Swimming laps
• Aerobic dancing
• Jogging or running
• Bicycling 10 miles per hour or faster
• Heavy gardening (continuous digging or hoeing)
To learn more about vigorous exercise, see What's the Best Energizing, Anti-Aging Workout?, Pressed for Time? Try this Workout Shortcut , and 7-Minute Fitness HIIT — and click here for an instructional brochure on that brief, high-intensity interval training (HIIT) workout.
"Obesity paradox" wilts under scrutiny
The second new study shed further light on the questions posed by the first study.
Previous research seemed to uncover an “obesity paradox”, in which — compared to heart patients of normal weight — overweight heart patients seem to live longer.
The new study was conducted by researchers from Northwestern University and the University of Texas (Khan SS et al. 2018).
This U.S.-based team examined data from more than 190,672 people — including data collected during in-person examinations — who were followed for an average of almost 17 years.
At the beginning of the study, all the participants were free of heart disease and BMI data was available for them.
During the follow-up period, the researchers looked for evidence of cardiovascular disease (coronary heart disease, stroke, heart failure and cardiovascular death), as well as death due to other factors.
While the results revealed similar life expectancies among normal weight and overweight people, those who were overweight had a higher risk of developing cardiovascular disease during their life and more years dealing with the effects of heart disease.
According to study co-author Dr. Sadiya Khan, a cardiologist from the Northwestern University Feinberg School of Medicine, “I get a lot of patients who ask, ‘Why do I need to lose weight, if research says I’m going to live longer?’ I tell them losing weight doesn’t just reduce the risk of developing heart disease, but other diseases like cancer. Our data show you will live longer and healthier at a normal weight.” (NU 2018)
Here are a few additional key takeaways from this large-scale study:
- Overweight men ages 40-59 were 21% more likely to have a stroke, heart attack, heart failure or cardiovascular death than normal weight men. Overweight women of the same age were 32% more likely to suffer from heart disease.
- Obese men ages 40-59 were 67% more likely to have a stroke, heart attack, heart failure or cardiovascular death than normal weight men. Obese women were 85% more likely to suffer these effects than normal weight women.
- Normal weight middle-aged men lived 1.9 years longer than obese men and 6 years longer than morbidly obese men. Normal weight men had similar longevity to overweight men.
- Normal weight middle-aged women lived 1.4 years longer than overweight women, 3.4 years longer than obese women and 6 years longer than morbidly obese women.
Dr. Khan made this central point: “A healthy weight promotes healthy longevity or longer health span in addition to lifespan, so that greater years lived are also healthier years lived. It’s about having a much better quality of life.”
Vitamin D may lower the risk of heart-related death
Finally, the results of another recent study suggest that you can also reduce your risk of death from heart disease by maintaining healthy vitamin D levels (Degerud E et al. 2018).
This latest study, from researchers at Norway’s University of Bergen, found that adults who suffer from heart disease and maintain adequate — i.e., above average — blood levels of vitamin D can lower their risk of death from heart disease by 30%.
The study included about 4,000 patients with cardiovascular diseases, whose average age was 62 at the start of the study. The study began in 2000 and the participants were followed for 12 years.
And the results linked vitamin D blood levels lower than 17 ng/mL or above 40 ng/mL (i.e., 42 to 100 nmol/l) with a greater risk of dying from cardiovascular disease.
According to Professor Jutta Dierkes at the University of Bergen, “We discovered that the right amount of vitamin D reduces the risk of death substantially ... too much or too little increase[d] the risk.”
This finding fits fairly well with the advice proffered by vitamin D researchers like Michael F. Holick, Ph.D., M.D., of Boston University Medical Center, who recommends a minimum blood level of 30 ng/mL (75 nmol/L) — which is associated with lower risk of major diseases, including certain cancers.
Although Dr. Holick and other vitamin D experts recommend blood levels up to 100 ng/mL (250 nmol/L), the new evidence from Norway suggests it may be wise to stick closer to 40 ng/mL (100 nmol/L).
(Note: To convert nmol/l to ng/mL, divide nmol/L by 2.496, and to convert ng/mL to nmol/L, multiply ng/mL times 2.496.)
While epidemiological studies like this one can't prove a cause-effect relationship between body levels of a nutrient and risk for disease, their findings shouldn't be ignored.
Professor Dierkes recommends that people with heart disease get their vitamin D levels measured, to determine if supplementation is necessary — advice that really applies to everyone.
Fatty wild fish — such as wild salmon, albacore tuna, and sardines — are the only good food sources of vitamin D.
Unlike any other food, they provide very high levels of vitamin D, which rival the amounts delivered in vitamin D supplements and far exceed the levels in multivitamins or fortified milk.
Calculating your BMI by hand
If you are 5’5” tall and weigh 150 pounds, your BMI is 25, right on the edge between normal weight and overweight.
How did we get that figure?
BMI is calculated using the metric system, so convert pounds to kilograms and inches to meters, and then divide body weight by the square of body height. (You'll find many metric conversion websites online, including this one.)
150 pounds equals 68 kilograms, while 65 inches equals 1.651 meters, the square of which is 2.725 meters. So we divided 68 by 2.725, resulting in a BMI of 24.9 (rounded up to 25).
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