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| I hope this newsletter finds you and your family well. As all the summer months seem to, July has flown by. My oldest daughter is already heading back to college this weekend. I'm looking forward to more warm, sunny days to come in August.
Hydration and water intake are a bit controversial. Some studies have shown that it doesn't matter. Others even suggest more water may be bad for weight control. This study looked at urine osmolality as a measure of hydration and found an interesting correlation between hydration status and obesity.
Prediabetes affects 1 in 3 people. This condition of higher blood glucose is a known precursor to diabetes. It is also completely reversible through diet and exercise. But how much exercise do we need and how intense should it be? The answer in the second article may surprise you. Anyone who has children or worked with children knows that they can get a bit unruly at times. My mother had a solution and researches are now showing that she was definitely on to something. Check out the third article for the simple solution which may be a good tool to use even if you don't have ADHD. Click on the links the the left to check out our web site... |
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It's The Water!
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Inadequate hydration linked to higher risk of obesity
Staying hydrated may be more important in long-term health than previously thought. This study, from the
Annals of Family Medicine, found people who were inadequately hydrated had higher body mass indexes (BMI) and had a significantly higher chance of being obese than those who were adequately hydrated.
Summary of findings:
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PURPOSE Improving hydration is a strategy commonly used by clinicians to prevent overeating with the goal of promoting a healthy weight among patients. The relationship between weight status and hydration, however, is unclear. Our objective was to assess the relationship between inadequate hydration a
nd BMI and inadequate hydration and obesity among adults in the United States.
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METHODS Our study used a nationally representative sample from the National Health and Nutrition Examination Survey (NHANES) 2009 to 2012, and included adults aged 18 to 64 years. The primary outcome of interest was body mass index (BMI), measured in continuous values and also categorized as obese (BMI ≥30) or not (BMI <30). Individuals with urine osmolality values of 800 mOsm/kg or greater were considered to be inadequately hydrated. Linear and logistic regressions were performed with continuous BMI and obesity status as the outcomes, respectively. Models were adjusted for known confounders including age, race/ethnicity, sex, and income-to-poverty ratio.
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RESULTS In this nationally representative sample (n = 9,528; weighted n = 193.7 million), 50.8% were women, 64.5% were non-Hispanic white, and the mean age was 41 years. Mean urine osmolality was 631.4 mOsm/kg (SD = 236.2 mOsm/kg); 32.6% of the sample was inadequately hydrated. In adjusted models, adults who were inadequately hydrated had higher BMIs (1.32 kg/m2; 95% CI, 0.85-1.79; P <.001) and higher odds of being obese (OR = 1.59; 95% CI, 1.35-1.88; P <.001) compared with hydrated adults.
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CONCLUSION We found a significant association between inadequate hydration and elevated BMI and inadequate hydration and obesity, even after controlling for confounders. This relationship has not previously been shown on a population level and suggests that water, an essential nutrient, may deserve greater focus in weight management research and clinical strategies.
In a previous newsletter, I highlighted a
study that showed drinking 16 oz of water prior to a meal lead to significant weight loss over time. The current study, with 9,528 participants, shows that adequate hydration, as measured by urine osmolality, is an independent risk factor for higher BMI and obesity. In fact, the difference is almost 60% higher risk in the least hydrated people. As with most studies, the finding does not necessarily mean causation but since it is so simple to treat,, it makes sense to try it. The solution is simple, drink more water! It seems to make sense to drink around 16 ounces of water within 30 minutes prior to your meals. It may help more than weight. Poor hydration is associated with poor mood, headaches and constipation. Drink up!
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Walking briskly may outperform vigorous exercise in people with prediabetes
The 'gold standard' for prevention of diabetes is lifestyle changes. These recommendations include changes in diet, exercise, and weight loss. We typically recommend all three to anyone who is showing signs of glucose intolerance (elevated blood sugars) but are not at the level of diabetes. These people are at very high risk of proceeding to true diabetes over the next few years if significant lifestyle changes are not done. The optimal intensity of exercise isn't known and this study sought to find out what the best level of exercise should be recommended.
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Aims/hypothesis:
Although the Diabetes Prevention Program (DPP) established lifestyle changes (diet, exercise and weight loss) as the 'gold standard' preventive therapy for diabetes, the relative contribution of exercise alone to the overall utility of the combined diet and exercise effect of DPP is unknown; furthermore, the optimal intensity of exercise for preventing progression to diabetes remains very controversial. To establish clinical efficacy, we undertook a study (2009 to 2013) to determine: how much of the effect on measures of glucose homeostasis of a 6 month programme modelled after the first 6 months of the DPP is due to exercise alone; whether moderate- or vigorous-intensity exercise is better for improving glucose homeostasis; and to what extent amount of exercise is a contributor to improving glucose control. The primary outcome was improvement in fasting plasma glucose, with improvement in plasma glucose AUC response to an OGTT as the major secondary outcome.
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Methods:
The trial was a parallel clinical trial. Sedentary, non-smokers who were 45-75 year old adults (n = 237) with elevated fasting glucose (5.28-6.94 mmol/l) but without cardiovascular disease, uncontrolled hypertension, or diabetes, from the Durham area, were studied at Duke University. They were randomised into one of four 6 month interventions: (1) low amount (42 kJ kg body weight-1 week-1 [KKW])/moderate intensity: equivalent of expending 42 KKW (e.g. walking ~16 km [8.6 miles] per week) with moderate-intensity (50%
V.O2reserve
) exercise; (2) high amount (67 KKW)/moderate intensity: equivalent of expending 67 KKW (∼22.3 km [13.8 miles] per week) with moderate-intensity exercise; (3) high amount (67 KKW)/vigorous intensity: equivalent to group 2, but with vigorous-intensity exercise (75%
V.O2reserve
); and (4) diet + 42 KKW moderate intensity: same as group 1 but with diet and weight loss (7%) to mimic the first 6 months of the DPP. Computer-generated randomisation lists were provided by our statistician (G. P. Samsa). The randomisation list was maintained by L. H. Willis and C. A. Slentz with no knowledge of or input into the scheduling, whereas all scheduling was done by L. A. Bateman, with no knowledge of the randomisation list. Subjects were automatically assigned to the next group listed on the randomisation sheet (with no ability to manipulate the list order) on the day that they came in for the OGTT, by L. H. Willis. All plasma analysis was done blinded by the individuals doing the measurements (i.e. lipids, glucose, insulin). Subjects and research staff (other than individuals analysing the blood) were not blinded to the group assignments.
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Results:
Number randomised, completers and number analysed with complete OGTT data for each group were: low-amount/moderate-intensity (61, 43, 35); high-amount/moderate-intensity (61, 44, 40); high-amount/vigorous-intensity (61, 43, 38); diet/exercise (54, 45, 37), respectively. Only the diet and exercise group experienced a decrease in fasting glucose (p < 0.001). The means and 95% CIs for changes in fasting glucose (mmol/l) for each group were: high-amount/moderate-intensity −0.07 (−0.20, 0.06); high-amount/vigorous 0.06 (−0.07, 0.19); low-amount/moderate 0.05 (−0.05, 0.15); and diet/exercise −0.32 (−0.46, −0.18). The effects sizes for each group (in the same order) were: 0.17, 0.15, 0.18 and 0.71, respectively. For glucose tolerance (glucose AUC of OGTT), similar improvements were observed for the diet and exercise (8.2% improvement, effect size 0.73) and the 67 KKW moderate-intensity exercise (6.4% improvement, effect size 0.60) groups; moderate-intensity exercise was significantly more effective than the same amount of vigorous-intensity exercise (p < 0.0207). The equivalent amount of vigorous-intensity exercise alone did not significantly improve glucose tolerance (1.2% improvement, effect size 0.21). Changes in insulin AUC, fasting plasma glucose and insulin did not differ among the exercise groups and were numerically inferior to the diet and exercise group.
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Conclusions/interpretation:
In the present clinical efficacy trial we found that a high amount of moderate-intensity exercise alone was very effective at improving oral glucose tolerance despite a relatively modest 2 kg change in body fat mass. These data, combined with numerous published observations of the strong independent relation between postprandial glucose concentrations and prediction of future diabetes, suggest that walking ∼18.2 km (22.3 km prescribed with 81.6% adherence in the 67 KKW moderate-intensity group) per week may be nearly as effective as a more intensive multicomponent approach involving diet, exercise and weight loss for preventing the progression to diabetes in prediabetic individuals. These findings have important implications for the choice of clinical intervention to prevent progression to type 2 diabetes for those at high risk.
Prediabetes occurs when blood sugar levels are higher than normal, but not high enough to be considered diabetes. Some people refer to this condition as borderline diabetes or impaired glucose tolerance. It is increasingly common in our country with estimates as high as 1 in 3 people having this condition. In those over age 65, estimates are 1 in 2 people affected. The good news is that it can be completely reversed through changes in diet and exercise with loss of 7% of body weight (15 lbs if you weigh 200 lbs) and exercising 150 minutes weekly (20-30 minutes daily). What hasn't been known is the intensity of exercisenecessary to achieve this. We typically recommend walking as a moderate exercise to prevent progression to diabetes. This study sought to find out if more vigorous exercise is better than moderate exercise. Participants were divided into four groups. One followed a low-fat, low-calorie diet and moderate exercise equal to around 7.5 miles/week of brisk walking. The other participants were divided into three groups, one walking briskly for 7.5 miles/week, one higher volume of 11.5 miles/week of brisk walking and a third group with more vigorous exercise equivalent to jogging 11.5 miles/week. After 6 months, the first group (diet and exercise) had a 9% improvement in blood glucose. The moderate intensity, higher volume group had a 7% improvement, the moderate intensity lower volume group had a 5% improvement and the vigorous exercise group had a 2% improvement. These finding are a bit uprising. It seems that most of the improvement is with higher volume moderate intensity exercise. Increasing the length of your brisk walks is the best way to prevent progression to diabetes. Adding dietary change was minimally helpful, but I don't recommend the diet they used. It would be interesting to see what the changes would be if a Mediterranean diet was used instead of a low fat diet. I suspect there would be even more improvement. It would also be interesting to see if weight training was substituted. Based on this study, adding an additional half mile to your daily walk may significantly lower risk of progression to diabetes.
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Mothers Know This
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Burst of exercise may reduce ADHD symptoms
This study found that a 20-minute burst of moderate activity in men with symptoms of attention-deficit/hyperactivity disorder (ADHD) improved energy and motivation. They had lowered feelings of confusion fatigue and depression before performing a mental task.
Summary of findings:
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Purpose: Little is known about whether acute exercise affects signs or symptoms of attention deficit/hyperactivity disorder (ADHD) in adults. This experiment sought to determine the effects of a single bout of moderate-intensity leg cycling exercise on measures of attention, hyperactivity, mood, and motivation to complete mental work in adult men reporting elevated ADHD symptoms.
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Methods: A repeated-measures crossover experiment was conducted with 32 adult men (18-33 yr) with symptoms consistent with adult ADHD assessed by the Adult Self-Report Scale V1.1. Measures of attention (continuous performance task and Bakan vigilance task), motivation to perform the mental work (visual analog scale), lower leg physical activity (accelerometry), and mood (Profile of Mood States and Addiction Research Center Inventory amphetamine scale) were measured before and twice after a 20-min seated rest control or exercise condition involving cycling at 65% V˙O2peak. Condition (exercise vs rest) × time (baseline, post 1, and post 2) ANOVA was used to test the hypothesized exercise-induced improvements in all outcomes.
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Results: Statistically significant condition-time interactions were observed for vigor (P < 0.001), amphetamine (P < 0.001), motivation (P = 0.027), and Profile of Mood States depression (P = 0.027), fatigue (P = 0.030), and confusion (P = 0.046) scales. No significant interaction effects were observed for leg hyperactivity, simple reaction time, or vigilance task performance (accuracy, errors, or reaction time).
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Conclusion: In young men reporting elevated symptoms of ADHD, a 20-min bout of moderate-intensity cycle exercise transiently enhances motivation for cognitive tasks, increases feelings of energy, and reduces feelings of confusion, fatigue, and depression, but this has no effect on the behavioral measures of attention or hyperactivity used.
I remember my mother making my brothers and I go out of the house and run laps if we were getting too unruly. This study shows she was on to something! This study showed that although specific hyperactivity levels were not decreased, the subjects felt better. While all of us may not have ADHD, it makes sense to take a 20 minute walk prior to starting a cognitive project or studying. It may very well energize us and help us to focus and possibly perform better.
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Thank you for taking the time to read through this newsletter. I hope you have found this information useful as we work together to optimize your health.
Water is important for our health. While there is a bit of controversy over exactly how much we need, I would shoot for at least 64 ounces daily and more may be better. You do get water through foods so eating a diet high in vegetables and fruits is helpful in overall water content. It will help control weight and reduce your risk of obesity.
Walking briskly for just over 1.5 miles daily will significantly reduce your risk of progression to diabetes. It could be the best 20 minutes you spend. It's good to know that you don't have to even break a sweat to gain benefits.
Taking a 20-minute walk to improve concentration before starting a project makes sense, is certainly easy to do and may reduce our risk of progression to diabetes. It's a win-win!
As always, if you have questions about anything in this newsletter or have topics you would like me to address, please feel free to contact me by email, phone, or just stop by!
To Your Good Health,
Mark Niedfeldt, M.D.
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