Dr. David R Buyer, MD, MBA, FACP

Author: Cathie Wert

  • Blood Donation

    Woman giving bloodFive million people in the United States get blood transfusions each year. Thirty-six thousand units of red blood cells, 7,000 units of platelets and 10,000 units of plasma are transfused each day. More than 6.8 million donors supply 13.6 million units collected, which can be split up and used for multiple types of transfusions. But despite these large numbers, blood shortages still occur: 38% of the population is eligible to donate but less than 10% do so. The biggest reason people don’t donate is that the thought of doing so never occurs to them.

    Reasons why people may be ineligible to donate include anemia, hepatitis B or C, HIV or being at high risk for having HIV, and travel to destinations with high risk of infectious exposures. With some exceptions, those taking regular medications are generally eligible to donate blood. Prescription blood thinners (e.g., Coumadin, Eliquis, Xarelto, Pradaxa, Plavix) and prostate medications (e.g., Avodart, Propecia, Proscar) are examples of prohibited medications. Those undergoing estrogen replacement therapy are not prevented from donating.

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    “Blood donation takes less than 90 minutes and is an easy way to help others.”

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    If you have had basal and squamous cell cancers removed within the past 12 months you are still eligible to donate. Blood cancers cause ineligibility, but other cancers that have not recurred for 12 months after completing treatment are acceptable. If you have controlled diabetes and high blood pressure, you are also eligible to donate.

    People with congestive heart disease are generally excluded from donating. However, those with coronary heart disease may be acceptable donors if there have been no symptoms, heart attack, bypass operation or angioplasty for six months. At one time, it was thought that donating blood decreased one’s cardiac risk. Unfortunately, this theory has not held up in clinical trials. People with heart disease should consult their physician prior to donation.

    This is a brief list of criteria and by no means exhaustive. Blood donation takes less than 90 minutes and is an easy way to help others.

  • Comparing Weight Loss Programs

    Apples, orange, lemon, pearWeight loss programs and diets are big business with $2.5 billion spent on these services in 2014. This is not surprising since 63% of adults have attempted to lose weight at some point. The largest three programs are Weight Watchers, Nutrisystem and Jenny Craig. How do the various programs stack up?

    One review looked at 141 different programs. They divided programs into very low-calorie diets (VLCD), self-directed diets and leading market-share programs (LMS). End-points were the amount of weight lost over the short-term (<12 months) and long-term (12+ months). Selected diets were compared with controlled education. Costs of the programs studied varied between zero and $682 per month. The review did not evaluate physical activity, behavioral and social support, medication or supplement use. The average age of people in the studies was 37–57 years old and the subjects were predominantly women. VLCD diets included were Health Maintenance Resources, Medi-fast and Opti-fast. Self-directed diets were Atkins, Biggest Loser, eDiets, LoseIT and Slimfast. LMS diets were Jenny Craig, Weight Watchers and Nutrisystem.

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    “Weight Watchers was the most cost-effective diet while Jenny Craig had the greatest sustained weight loss. Nutrisystem was good at short-term weight loss.”

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    Results are summarized in the table. Due to heterogeneity of the studies, it is difficult to compare the diets and only generalizations can be made. Weight Watchers was the most cost-effective diet while Jenny Craig had the greatest sustained weight loss. The VLCD were superior to other programs in the short term. Nutrisystem, grouped as a leading market share diet in this study, was good at short-term weight loss as well. No trials were continued to evaluate long-term effects. VLCD had triple the risk of gallstones compared to low-calorie diets. Results of the self-directed diets were mixed. Contemporary literature reflects social changes and thinking.

    These findings show that many programs are helpful in various settings and different programs have different short- and long-term outcomes. The authors conclude that Weight Watchers and Jenny Craig are the two best diets studied.

    Comparing Weight Loss Programs — Very Low-Calorie Diets Chart

    Comparing Weight Loss Programs — Self-Directed Diets

    Comparing Weight Loss Programs — Leading Market-Share Diets

  • Sedentary Time

    A woman relaxing with her dogOne way to view activity level and health outcome is to measure health outcomes based on amount of non-active time. However, caution must be used in interpretation because moderate activity as recommended is not necessarily the opposite of being sedentary. A meta-analysis assessed sedentary time with risk for disease, mortality and hospitalization. This, in combination with studies on moderate and vigorous activity, helps to provide a more complete picture of activity level and health outcomes.

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    “Maintaining a minimum amount of physical activity and breaking up sedentary time with walks or non-sitting tasks would appear to be beneficial to health.”

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    The study defined being sedentary as less than 1.5 METS (eg. sitting, watching TV, reclining) and evaluated overall hours of sedentary behavior or sitting hours per day or week. Out of almost 21,000 studies 41 met inclusion criteria. The analysis found that greater sedentary time was associated with all-cause mortality, cardiovascular disease incidence, cancer incidence and type 2 diabetes incidence. Of the cancers, breast, colon, colorectal, endometrial and epithelial ovarian cancers showed increased incidence. Further, sitting fewer than eight hours a day had a 14% lower risk for potentially avoidable hospital admissions. When evaluating sedentary time along with level of activity, there was a 30% less relative risk of all-cause mortality in those with high versus low levels of physical activity. It appears that there is an interaction between amount of non-activity and amount of activity, with those who are more physically active having less impact of sedentary time on their health.

    Based on this analysis, both activity and non-activity time is important. Currently guidelines do not state how much sedentary time is “acceptable.” The amount may be different if sitting at work versus sitting in leisure time. We also don’t know if being sedentary and awake longer is better or worse than sleeping more. Much more research is needed. In the meantime, maintaining a minimum amount of physical activity and breaking up sedentary time with walks or non-sitting tasks would appear to be beneficial to health.

  • General Physical Activities Defined by Level of Intensity

    Almost every occupation requires some mix of light, moderate, or vigorous activities, depending on the task at hand. To categorize the activity level of your own position, ask yourself: How many minutes each working day do I spend doing the types of activities described as light, moderate, or vigorous? To arrive at a total workday caloric expenditure, multiply the minutes spent doing activities within each intensity level by the kilocalories corresponding to each level of intensity. Then, add together the total kilocalories spent doing light, moderate, and vigorous activities to arrive at your total energy expenditure in a typical day. Use this handy chart to help calculate the calories burned based on your activities.

    Download the activity guide (PDF file) here |

     

  • Physical Activity Recommendations

    The amount of physical activity recommended for adults is 150 minutes of moderate activity per week, along with muscle-strengthening activity of all muscle groups twice a week. Alternatively, one may get 75 minutes of vigorous activity a week with muscle strengthening twice a week. A mixture of moderate and vigorous activity is also acceptable. Doing ten minutes of activity at a time still counts toward the weekly total. Only 54% of people in Illinois get the recommended amount of physical activity while 24% do not get any leisure-time activity, based on data from 2013.

    So what is moderate and vigorous activity? Activity levels can be roughly assessed using breathing and heart rate. With moderate activity, one can talk in sentences, while with vigorous activity one can only say a few words before needing to take a breath. Using heart rate as a guide, moderate activity is when the heart rate reaches 50–70% of maximum for one’s age, and 70–85% is considered vigorous activity. Maximum heart rate is computed as 220 minus age. Increasing heart rate to the maximum and beyond is not necessary.

    Activities that are considered moderate intensity include walking between 3–4.5 mph, hiking, biking 5–9 mph, yoga and dancing, to name a few. Housework, including scrubbing the floor or bathtub on hands and knees, washing windows and sweeping also are moderately-vigorous activities. Vigorous activity examples include walking, jogging or running more than 5 mph, biking over 10 mph, competitive ballroom dancing and other competitive sports. Household vigorous activity includes moving heavy furniture, carrying 50 pounds or more and shoveling more than 10 pounds a minute. A more extensive list of activities can be found here.

  • Effect of Exercise on Mortality

    Woman doing plank

    Since 2008 the U.S. government has issued activity guidelines. The recommendations are reported in this article. Of the 150 minutes weekly of moderate-intensity activity, vigorous activity can be substituted with a 1:2 ratio of minutes needed. However, cardiorespiratory and metabolic fitness is a better indicator of morbidity and mortality than the amount of time of activity. So despite the recommendations, which are for a minimum amount of activity, is there benefit to more vigorous activity?

    One study evaluated the proportion of moderate or vigorous activity that was accounted for by vigorous activity and whether more vigorous activity decreased mortality. Studies have also examined if there is an upper threshold of vigorous activity that exists such that mortality is not improved or worsened.

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    “Based on these two analysis, increasing activity prolongs longevity and, up to a point, increasing vigorous activity is more beneficial than moderate activity. “

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    The study was performed on 204,000 people in Australia between the ages 45 and 75. This is 10% of the entire population in New South Whales. Self-reported activity intensity is a better predictor of mortality than total amount of activity so self-reported activity data was assessed using a questionnaire. Vigorous activity was defined as “activity that made you breathe harder or puff and pant, like jogging, cycling, aerobics, competitive tennis, but not household chores or gardening.” Moderate activity examples were “gentle swimming, social tennis, vigorous gardening or work around the house.”

    The questionnaire collected data on minutes of walking and minutes of moderate-vigorous physical activity. Covariate analysis with age, sex, education, marital status, urban/rural, BMI, smoking, physical function, alcohol, fruit and vegetable consumption, and total MVPA was also done. The sample was heterogeneous with 64% obese and 55% without any vigorous activity. Sixteen percent of respondents had between 0 and 30% of total activity time being vigorous, and 28% had 30% or more of their activity being vigorous.

    Results are shown in the table below. Increasing amount of time of activity decreases mortality and any report of physical activity decreased mortality 9–13%. This protective effect of activity carried across all subgroups including those with and without cardio-metabolic disease. Another meta-analysis showed that walking pace, not time spent walking, is associated with longevity.

    Effect of Exercise on Mortality — Mortality compared to no activity

    There are a lot of people in the United States doing highly intense physical activity. In 2013, 541,000 people completed a marathon and in 2012 there were 510,000 USA triathalon members. Additionally, there are a lot of people doing high-intensity interval training. If increased intensity activity is beneficial, then is there an upper limit to the amount of vigorous activity, at which point it becomes detrimental?

    An evaluation was done using pooled analysis of 6 cohorts in the National Cancer Institute Cohort Consortium analysis of BMI, physical activity and mortality. Estimated leisure time physical activity (LTPA) based on METs and hours per week of exercise were reported. This was analyzed accounting for covariates of age, sex, race/ethnicity, education, smoking, cancer history, heart disease history, alcohol and marital status. The sample consisted of 661,000 people with median follow up over 14 years. Median age at entry was 62, median leisure-time physical activity (LTPA) was 8 MET hours/week (150 minutes is 7.5 MET hours/week).

    The study showed younger, married, non-smokers, with lower BMI and fewer comorbidities exercised the most. Again, compared to no activity, any level of activity decreased mortality. In subgroup analysis, any level of vigorous activity decreased mortality by 20%, even if less than the recommended amount. The table below shows the decrease in mortality compared with activity level. Cardiovascular death was minimized at 3–5 times the recommended amount of activity and increased again at 10 or more times over the minimum. However, those doing 10 or more times over the minimum recommendation had a 31% lower risk of cancer death.

    Based on these two analysis, increasing activity prolongs longevity and, up to a point, increasing vigorous activity is more beneficial than moderate activity. Although these studies included people with cardiovascular disease, we do not know the severity of this or other illnesses. The results may not be generalizable to people with more severe illness, but the overall recommendation that increasing activity is beneficial seems to make sense for everyone, regardless of overall health.

    Effect of Exercise on Mortality — Amount of physical activity and mortality reduction