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Sports Medicine Blog

Information shared here is not intended to be a substitute for professional or medical advice on personal health matters. For personal medical advice, or if you are concerned about a medical condition or injury, please see your healthcare provider for evaluation and care.

  1. Mediterranean Diet and Cardiovascular Events in Women

    Mediterranean Diet associated with fewer cardiovascular events in middle aged women, according to a study published online December 7, 2018 in the JAMA Network. 25,994 US women in the Womens Health Study were evaluated and then followed for 12 years. Those who adhered closest to the Mediterranean Diet, a diet high in fresh fruits and vegetables, nuts and seeds, whole grains, with some chicken and fish, and low in red meat and dairy products, had about a 25% lower relative risk of cardiovascular events than those who adhered the least. The researchers found that the causes were most likely reduced overall inflammation, lowered blood glucose and increased insulin sensitivity, as well as reduced body mass index. Blood pressure was also somewhat lowered, and the lipid profiles were also improved. This compares favorably with the risk reduction seen with statins.

    Posted by Jessica Seaton
  2. Bone Density and Swimming

    I just did a Pub Med search for swimming and bone density in humans. The bottom line is swimming does not improve bone density. In order to improve bone density you need impact and resistance. Swimmers should include resistance training, along with balance and flexibility training in order to prevent falls as they get older and are more likely to have osteoporosis. Swimmers who are younger should probably cross train with resistance and impact exercises.

    Here are some articles for your enjoyment:
    A meta-analysis published in 2016 covering 2004-2014 found 18 studies that reported that swimming did not increase bone mineral density. [Rev Bras Reumatol Engl Ed. 2016 Jul-Aug;56(4):345-51. doi: 10.1016/j.rbre.2016.02.013. Epub 2016 Mar 11.]

    A 2008 study examined runners and swimmers at the Senior Olympic Games and compared them to sedentary controls. Runners and swimmers both had higher bone mineral density, with the runners topping the swimmers. The swimmers in this study may have also been doing weight training. [Osteoporos Int. 2008 Oct;19(10):1457-64. doi: 10.1007/s00198-008-0590-6. Epub 2008 Mar 20.
    The effect of moderate impact exercise on skeletal integrity in master athletes.
    Velez NF1, Zhang A, Stone B, Perera S, Miller M, Greenspan SL.]

    Sedentary middle-age women trained 3 times per week either playing soccer, swimming at a moderate intensity, or swimming with high intensity intervals. Bone turnover markers increased in the soccer players but were unchanged in either of the swimming groups. [Eur J Appl Physiol. 2015 Dec;115(12):2671-9. doi: 10.1007/s00421-015-3231-8. Epub 2015 Aug 9.
    Effects of soccer vs swim training on bone formation in sedentary middle-aged women.
    Mohr M1,2, Helge EW3, Petersen LF4, Lindenskov A5, Weihe P6, Mortensen J7,8, Jrgensen NR9, Krustrup P3,10.]

    Another study had 58 women diagnosed with osteoporosis either do land exercises or water exercises for 10 months. At the end of the study period, those doing land exercises had improved muscle strength, flexibility, and bone density as compared to the water exercise group. [Ortop Traumatol Rehabil. 2014 May-Jun;16(3):319-25. doi: 10.5604/15093492.1112533.
    The effect of land versus aquatic exercise program on bone mineral density and physical function in postmenopausal women with osteoporosis: a randomized controlled trial.
    Murtezani A1, Nevzati A2, Ibraimi Z3, Sllamniku S4, Meka VS1, Abazi N1.]

    A 2012 study comparing women who swam and currently swim at least 2 hours a week, with other reasonably active women, found that bone mineral density was not affected by swimming. [Ortop Traumatol Rehabil. 2014 May-Jun;16(3):319-25. doi: 10.5604/15093492.1112533.
    The effect of land versus aquatic exercise program on bone mineral density and physical function in postmenopausal women with osteoporosis: a randomized controlled trial.
    Murtezani A1, Nevzati A2, Ibraimi Z3, Sllamniku S4, Meka VS1, Abazi N1.]

    A 2016 study concluded that swimming during childhood and adolescence, while having many health benefits, does not improve bone mineral density. [Sports Med. 2016 Mar;46(3):365-79. doi: 10.1007/s40279-015-0427-3.
    The Effect of Swimming During Childhood and Adolescence on Bone Mineral Density: A Systematic Review and Meta-Analysis.
    Gomez-Bruton A1,2,3, Montero-Marn J4,5, Gonzlez-Agero A1,2,3, Garca-Campayo J5,6,7, Moreno LA2,3,8, Casajs JA1,2,3, Vicente-Rodrguez G9,10,11.]

    A 2015 study looking at adolescents found that for males, swimming was associated with lower bone mineral content and density. The results were less clear for females.
    [Scand J Med Sci Sports. 2015 Dec;25(6):e589-602. doi: 10.1111/sms.12378. Epub 2014 Dec 30.
    The effects of swimming training on bone tissue in adolescence.
    Gmez-Bruton A1, Gonzlez-Agero A1,2, Gmez-Cabello A1,3, Matute-Llorente A1, Casajs JA1, Vicente-Rodrguez G1.]
  3. Better Diet, Better Brain

    A study published in June 2018, The Rotterdam Study, showed that a better quality diet is related to larger brain tissue. This can have an impact on an aging brain and the risk for dementia. Brains do tend to shrink with age. However, a diet high in vegetables, fruit, whole grains, nuts, dairy, and fish and a low intake of sugar-containing beverages was associated with larger brain volumes.
  4. Exercise and Pregnancy

    by , January 21st, 2018 at 07:48 PM (Sports Medicine Blog)
    The American College of Obstetricians and Gynecologists reaffirmed the importance of exercise during pregnancy in an opinion paper that can be accessed here. They point out that regular physical exercise during pregnancy improves physical fitness and well-being, along with helping with weight management and reducing the risk of gestational diabetes. The statement is thoroughly referenced and goes into great detail for those interested in finding out more about exercise and pregnancy.
  5. Green Leafy Vegetables and Your Mind

    by , January 9th, 2018 at 02:54 PM (Sports Medicine Blog)
    A recent longitudinal study published December 20, 2017 online in [I]Neurology [I] found that older people who consumed 1-2 servings of green leafy vegetables daily were cognitively 11 years younger than those who rarely or never consumed green leafy vegetables. The study involved 960 individuals as part of the Rush Memory and Aging project with the average age of 81 years, average education of 14.9 years, and mean follow-up of 4.7 years. The researchers were able to tease out the phytonutrients most responsible for the beneficial effects: folate, lutein, and carotenoids. Green leafy vegetables include spinach, kale, collards, and dark lettuce. Aside from this study, research has been done on the MIND diet, which is a modification of the DASH diet and Mediterranean diet, emphasizing green leafy vegetables. This diet also is associated with a decrease in cognitive decline. So eat those green leafy vegetables!
    Tags: diet, mind
  6. Calorie Restriction v. Exercise for Weight Loss

    by , December 18th, 2017 at 05:09 PM (Sports Medicine Blog)
    A recent study focused on the effect of exercise or caloric restriction on weight loss and certain metabolic markers. 80 abdominally obese middle-aged Asian men were either put in a group where they reduced their caloric intake by 500 calories a day, or in a group that exercised (200-300 minutes a week) where their goal was to increase their caloric expenditure by 500 calories a day. After 24 weeks both groups lost approximately the same amount of weight. However the exercise group showed a greater decrease in overall inflammation, improved insulin sensitivity (important in preventing diabetes), and a better adipokine (hormones secreted by fat) profile. This study is interesting in that it was able to separate the effects of exercise and diet.

    --Jessica Seaton
  7. Protein and Fatigue

    by , December 18th, 2017 at 05:07 PM (Sports Medicine Blog)
    A study that should be of interest to USMS members, especially since many are also triathletes, has recently been published (The Effect of Higher than Recommended Protein Feedings Post-Exercise on Recovery Following Downhill Running in Masters Triathletes by Doering TM et al. International Journal of Sport Nutrition and Exercise Metabolism, in Press, August 2016). The investigators determine the effect of high versus moderate protein intake on the decrease in muscle function and fatigue following intensive exercise in a group of masters triathletes. This is a question of interest to all masters athletes since recent scientific data have suggested that the rate of both muscle repair and remodeling following exercise induced muscle damage become slower as we age.
    The study was conducted with 8 male masters triathletes (average age of ~52 2 years). Each subject underwent two trials where they received specified amounts of protein during the recovery from morning testing periods. The order of the trials was randomized and during one they received a total of 1.05 g/kg (moderate protein intake [MPI]), while during the other they received 1.95 g/kg (high protein intake [HPI]).
    The cycling time trial performance was not differentially affected by HPI compared to MPI, so it does not appear that the HPI significantly benefited cycling performance. In both trials the afternoon peak isometric torque was decreased in comparison to the morning value but in the HPI trials the decrease in peak isometric torque was significantly less than that seen in the MPI trial, resulting in a moderate beneficial effect. Additionally, the individual perception ratings indicated that HPI provided a large beneficial effect on fatigue: reducing the fatigue that the subjects felt in the afternoon after the 30 minute run earlier in the day much more than the MPI.
    The authors conclude that, in comparison with MPI, HPI accelerates recovery of muscle function and lowers perceptions of fatigue. The three protein boluses of MPI each contained ~0.3 g/kg of whey protein. For a 70 kg person (the standard size of an average adult male) this would equal about 20 grams of protein, which is the amount you would see recommended on the label of a protein supplement. So, if you usually drink about three glasses of protein supplement (each glass separated by about 2 hours) following an intense swimming event; then if you double the amount of protein supplement in each serving you would be taking in the rough equivalent to the HPI used in this study. This study suggests that this could be helpful to decrease your perception of fatigue and accelerate the recovery of your muscle function. However, as we age we also need to keep in mind the total number of calories we are ingesting via the protein supplement and maybe adjust our caloric intake in the rest of our diets so we are not taking in more calories than we need.
    Tags: protein, recovery
  8. The Effect of Exercise on Sitting Time

    By now most of us have heard that prolonged sitting has many adverse health effects. We've also been told that in general working out and then sitting all day does not make the situation much better. This new review article published in The Lancetlooked at the effect of physical activity and sedentary behavior with all-cause mortality. They found that daily sitting time did not have an effect on those in the most active quartile of physical activity. The people in the most active quartile did the equivalent of moderate exercise for an 60-75 minutes per day, everyday. Interestingly, those who sat the least but were also the least active otherwise, had a significantly increased risk of dying. So just being on your feet all day does not give you the same benefit as exercise. Another interesting fact was that regardless of physical activity, 3 or more hours per day of watching television was associated with increased mortality.
  9. Possible new blog post: Exercise and Weight Loss in Women

    TIME magazine in April of 2009 published an article stating that exercise possibly does not have the same effect in men and women, and that women possibly do not lose weight with exercise because they eat more afterwards. Two researchers in the UK, David Stensel, Ph.D. and Kevin Deighton, Ph.D., conducted two studies to examine this issue. The first study looked at the hormonal response to calorie restriction and to exercise in women. The researchers found that appetite perceptions were higher during food restriction but not after exercise. This was confirmed by the appetite increasing hormone being higher with food restriction than during exercise. An appetite suppressing hormone, the peptide YY, was high during exercise and low during food restriction. In the second study, men and women were compared hormonally and found to have the same response to exercise as far as appetite perception and ghrelin. When presented with a buffet of food post exercise, the womens response was the same as the mens. Together these studies demonstrate that exercise can be helpful for weight loss and weight management in both men and women.
  10. Fish Oil and Exercise in Older Women

    Fish Oil and Exercise in Older Women

    A recent study published on PLOSOne found that fish oil has many beneficial effects for older women who exercise. This small study recruited 24 females between 65 and 67 years old who were in good health. Half were given 3 g worth of fish oil supplements (2 g EPA and 1 g DHA)per day, while the other half were given the same amount in organic olive oil. A side note here is that olive oil has many benefits for the cardiovascular system, so it may not always be the best placebo. Extensive measurements were taken preceding the experimental phase, as well as at the conclusion. The experimental phase was 12 weeks, during which the women ate and exercised as usual. The group who supplemented with fish oil showed a significant increase in resting metabolic rate (14%), energy expenditure during exercise (10%), a 19% increase in the rate of fat oxidation during rest and a 27% increase during exercise. Fish oil consumption lowered triglyceride levels by 29% and increased lean mass by 4% and functional capacity by 7%. No changes were noted in the olive oil group.

    The study is available here in full text.
  11. Nuts and Cardiovascular Disease

    by , January 29th, 2016 at 06:19 PM (Sports Medicine Blog)
    A meta-analysis of 61 trials performed by Tufts researchers in Boston found that tree nut intake lowers total cholesterol, LDL cholesterol, triglycerides, and another cardiovascular disease marker, ApoB. The trials examined lasted from 3 to 26 weeks. Interestingly, they found that the nut type was less important than the quantity of nuts consumed. More was better with stronger effects being noted for those consuming more than 60 grams per day of nuts. Nuts are high in calories, so adding a lot of nuts to your diet could also add on weight, unless you consume fewer calories elsewhere.

    Link to abstract:

    Jessica Seaton
  12. Older Athletes Have a Younger Fitness Age

    by , January 29th, 2016 at 04:07 PM (Sports Medicine Blog)
    This NYT article reviews some recent studies that determine a person's "fitness age" using an online calculator. A physician/triathlete contacted the developer of the calculator and recommended that the Norwegian group study the athletes entered in the 'Senior Olympic Games" Almost all athletes participated and the average difference between chronological age and fitness age was 25 years! The group is still working on parsing out data to see if endurance sports - like swimming and running - have lower fitness ages than other sports. The article includes a link to the online fitness calculator.

    Cathy Fedako
    Tags: age, fitness
  13. Mediterranean Diet and Breast Cancer

    by , January 25th, 2016 at 07:43 PM (Sports Medicine Blog)
    A study published in the September 14, 2015 edition of JAMA Internal Medicine examined the data from the PREDIMED study that examined diet and risk for cardiovascular disease. In this secondary analysis, the researchers looked to see what effect two different dietary interventions would have on the incidence of breast cancer. The two intervention groups were advised to eat a Mediterranean style diet: high in vegetables, fruits, fish, and olive oil. One group was given a liter of extra virgin olive oil per week to use and share with their families. Another group was given a daily supply of nuts: 15 g walnuts, 7.5 grams almonds, 7.5 grams hazelnuts. The control group was advised to follow a low fat diet. Compared with the control group, the Mediterranean diet with extra virgin olive oil had a 68% reduction in breast cancer incidence. There was also a reduction in the nuts group, but not statistically significant. Limitations of the study included a lack of universal screening for breast cancer prior to the study, the small number of women who did get breast cancer, and the fact that all the women were while, postmenopausal, and at high risk for cardiovascular disease. Previously the researchers did show that this diet did reduce the risk for cardiovascular disease. There doesnt seem to be a down-side to eating a Mediterranean type diet rich in olive oilwhether to prevent heart disease or to prevent breast cancer.

    Jessica Seaton
  14. Sleep and Insulin Sensitivity

    by , January 19th, 2016 at 08:05 PM (Sports Medicine Blog)
    Research presented at The Obesity Society Annual Meeting in Los Angeles found that a night of sleep deprivation affects insulin sensitivity to a similar degree as 6 months of a high fat diet in obese dogs. We dont know if the same applies to humans from this study. But we can extrapolate that lack of sleep can affect insulin sensitivity of the cells. Human studies have shown that poor sleep is associated with weight gain. Getting adequate sleep is one of many factors that can prevent diabetes.
    Jessica Seaton
  15. More Diet and Cognitive Function

    by , November 13th, 2015 at 08:45 PM (Sports Medicine Blog)
    Diet and Cognitive Function

    The August 12, 2015 edition of Nutrients (open access) had an interesting review article on diet and cognitive deficits. Here are some of the points I found most interesting:
    The reviewers found that mid-life BMI could be more important in predicting a decline in cognitive functioning than late life BMI. Low BMI is often associated with illness, so its much harder to tease out the effect of BMI in late life.
    Obesity is associated with systemic inflammation, metabolic syndrome, and reduced cardiovascular fitness. Any of these conditions affect cognition.
    Some studies have shown that a diet high in fat and refined sugars is correlated with impaired hippocampal function and the associated impaired memory. Interestingly, this impairment also reduces sensitivity to internal signals of hunger, which in turn promotes overeating and obesity.
    Other studies looked at the types of fats that people were eating. Some studies show that higher intake of saturated fatty acid is associated with impaired memory. Other studies show that a higher omega-3 to omega-6 polyunsaturated fat ratio was associated with a lower risk of cognitive decline. That would be a diet rich in fish and nuts and seeds and lower in meat and poultry.
    High intake of simple sugar has also been associated with lower cognitive function. Sugar can increase inflammation in the body and brain.
    Long chain polyunsaturated fatty acids such as docosahexaenoic acid (DHA) may help reduce the risk for cognitive decline. Studies have gone both ways, showing benefit and no benefit. When compared to animal studies, animals were supplemented for more than 10% of their (short) lifespan. For humans this would mean supplementing for more than 6-8 years for an effect to be noticed. So the time to start would be in midlife.
    Curcumin, the active ingredient in the Indian spice turmeric, has also been shown to be helpful in preventing cognitive decline, although much more research in this area needs to be done. Curcumin is sold in supplement form. However, when buying curcumin, it is important to note that absorption can be an issue. There are now various products on the market that improve absorption over eating it raw or as a spice in food.
  16. Diet and Cognitive Function

    by , September 21st, 2015 at 08:16 PM (Sports Medicine Blog)
    Scientific American posted a very good article on the Mediterranean diet, the MIND diet, and cognitive function. The article explains some of the difficulties in doing whole diet research on humans. The article goes on to explain how the MIND diet is a variation of the Mediterranean diet that would be easier for Americans to adhere to. If you're interested in this topic, I would suggest following this link:
  17. Optimal Brain Function and Exercise

    by , September 14th, 2015 at 08:16 PM (Sports Medicine Blog)
    PLOSOne published a study on the effects of exercise on cognition in individuals older than 65 year. 100 sedentary individuals with no cognitive deficits and who were not insulin-dependent diabetics, had no significant hearing or visual problems, and no major cardiorespiratory or musculoskeletal impairments in the last two years, were recruited for the study. They were then randomized to either no intervention, 75, 150, or 225 minutes of semi-supervised aerobic exercise per week. The study was conducted over a 26 week period of time. Over the course of the intervention, those who exercised had improved cardiorespiratory fitness, with those exercising longer and more intensely having the greatest benefit. All the exercise groups improved their attention span and their visuospatial processing, with more intense exercise having more benefit. Those who adhered to the protocols saw more improvement than those who didn't. An individual's cardiorespiratory fitness at the end of the study was the best predictor of cognitive gains.
    This study is interesting because it was prospective: they all started out the same, and those that exercised improved compared to those who didn't. It is also interesting because even those in the 75 minutes per week group showed improvement. However, more was better.
  18. Breath-Holding

    Morbidity and Mortality Weekly Report (MMWR) from the Centers for Disease Control and Prevention recently published an article: Fatal and Nonfatal Drowning Outcomes Related to Dangerous Underwater Breath-Holding Behaviors New York State, 19882011.
    This report identifies dangerous underwater breath-holding behaviors (DUBBs) that increase the risk of breath-hold blackout and drowning. Three DUBBs included: intentional hyperventilation before submerging/swimming; attempting breath-holding for as long as possible while underwater; and hypoxic training (prolonged underwater swimming or extended breath-hold intervals. Hyperventilation and hypoxic training were seen mostly in experienced swimmers.
    Swimmers and coaches need to be aware that these DUBBs are associated with blackout and drowning and so should be avoided.

    --Jane Moore
  19. Exercise, Weight Loss, and Inflammation

    A recent study focused on the effect of exercise or caloric restriction on weight loss and certain metabolic markers. 80 abdominally obese middle-aged Asian men were either put in a group where they reduced their caloric intake by 500 calories a day, or in a group that exercised (200-300 minutes a week) where their goal was to increase their caloric expenditure by 500 calories a day. After 24 weeks both groups lost approximately the same amount of weight. However the exercise group showed a greater decrease in overall inflammation, improved insulin sensitivity (important in preventing diabetes), and a better adipokine (hormones secreted by fat) profile. This study is interesting in that it was able to separate the effects of exercise and diet.

    --Jessica Seaton
  20. Fructose and Diabetes

    A recent article in the March 2015 online edition of the Mayo Clinic Proceedings looked at data from both animal and human studies and found that added sugars (e.g., sucrose and high fructose corn syrup) contribute to the development of diabetes and related problems, including cardiovascular disease. Sucrose consists of a molecule of glucose and a molecule of fructose. The authors implicate the fructose molecule. The point out that the same associations are not found to the same extent with glucose and starchy foods per se. They point out that the World Health Organization recommends no more than 5% of one's daily energy intake come from added sugars. The US Institute of Medicine allows up to 25% of calories from added sugars. It is worth noting that the sugar lobby exerts enormous pressure on US organizations making dietary recommendations. Eating unprocessed or whole foods eliminates most added su
    gars. If you haven't seen the film Fed Up , I would highly recommend it. The filmmakers encouraged viewers to try one week without any added sugars. It is much more difficult than you'd think!
    --Jessica Seaton, DC
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