Drinking Too Much Water Can Be Harmful And Even Fatal

Drinking large quantities of water has been widely promoted over the past few years as a means of maintaining health, improving appearance, controlling weight, and preventing dehydration. It is now not unusual to see people regularly carrying and sipping from water bottles. Eight 8-ounce glasses of water a day has been commonly recommended as the minimum requirement. However, the evidence shows that this recommendation has little scientific basis. In addition, excess water consumption can be harmful and even fatal.

A June 4, 2009 article by Karen Bellenir, in the online Scientific American, a highly-respected journal, analyzed the origins of the 8 glass a day recommendation and presented the opinions of scientists in the area of hydration. The conclusion was that there was no scientific basis for the recommendation. Some key points from the article:

• Most people do not have to drink 64 ounces of water per day.
• Water needs differ widely among individuals and depends on many factors including body size, physical activity, ambient temperature and humidity.
• Much of our fluid needs are met from the water content in food.
• The only people who benefit from drinking large amounts of water are those who sweat a lot due to their participation in heavy physical activity, especially in hot environments, and people with specific medical conditions such as kidney stones or urinary tract infections.
• For hydration purposes, all drinks composed largely of water, including milk, juice, coffee, and tea are roughly equivalent to drinking plain water. While caffeine does somewhat stimulate urination, the net effect of these drinks is to provide the body with water. Only alcoholic beverages cause a net water loss.
• Drinking when thirsty is the best means of meeting our physiological need for fluid.
• Drinking water before meals does not reduce appetite or food consumption. However, eating foods that contain a lot of water but few calories (e.g. salad vegetables, fruit) can help control appetite.

One might think that excessive water-drinking is relatively harmless, with the only downsides being a bloated stomach, frequent urination, the expense of buying water and the inconvenience of carrying it. However, excessive water-drinking can actually be harmful and even fatal, as revealed in a June 21, 2007 article by Coco Ballentyne in the Scientific American online. Fatalities cited in the article include those of a woman who died after drinking 6 liters of water in a radio-station sponsored contest to see who could hold their urine the longest and an aspirant to a college fraternity who was prompted to drink excessive amounts of water. In addition, several athletes and military personnel have died after drinking excessive quantities of water in an effort to avoid dehydration.

The cause of these deaths is hyponatremia, which is a dangerously low concentration of sodium in the blood. Warning symptoms of this disorder include frequent urination, fatigue, headache, nausea, vomiting, and disorientation. Much of the damage is caused by entry of the excessive water into brain cells, with resultant brain swelling and damage.

It particularly dangerous for people engaged in endurance sports to drink excessive water because such physical activity stimulates the secretion of a hormone that tends to conserve water in the body by reducing excretion, even when drinking is excessive. This can reduce the kidneys’ ability to remove water from the bloodstream by 90%. Sport drinks, which contain sodium and other electrolytes as well as carbohydrates can help in preventing dangerous dilution of the blood, yet even excessive drinking of these fluids can cause hyponatremia. Drinking to thirst is still seen as the best recommendation.

Another possible negative effect of drinking too much water is the effect on blood pressure. A study by Callegaro et al. published in the Journal of Human Hypertension (vol. 21, pp. 564-570, July 2007) concluded that, after ingesting 500 ml (a little over 2 cups) of water, the systolic blood pressure of both subjects with and without high blood pressure rose 17-19 points and the diastolic blood pressure rose 14 points. These are major increases. While other studies did not observe this effect, it appears that excess water consumption may increase the possibility of high blood pressure. Thus, drinking to thirst is the best means of taking an amount of water that will avoid both dehydration and hyponatremia.

Omega-3 Fats from Fish Oil Raise Risk of High-Grade Prostate Cancer

It has been increasingly evident that there are trade-offs in the quest to get and stay healthy. In other words, there are actions we can take that will reduce the risk of one health problem, but increase the risk of another. One example is playing high-impact sports such as basketball, which is great for improving and maintaining physical fitness while having fun, but also increases the risk of sprains, strains and other musculoskeletal problems. Now, an article by Brasky et al. in the American Journal of epidemiology (published online April 24, 2011)  points up a trade-off involved in taking fish-oil supplements, which have been widely recommended for reducing the risk of cardiovascular diseases and other health problems.

The researchers analyzed blood samples of 3,461 men to measure levels of omega-3 fats (DHA and EPA from fish consumption), omega-6 fats (from common vegetable oils), and trans-fats (from hydrogenated oils in margarine, shortening, and processed foods). The men were then followed over a 7-year period in order to see the association of the different fat types to the incidence of prostate cancer. The hypotheses were that:

• Because of the anti-inflammatory effect of the omega-3 fats, men with the highest blood levels of them would have a lower incidence of prostate cancer
• Because of the inflammatory effect of the trans- fats, men with the highest blood levels of them would have a higher incidence of prostate cancer

Results
The statistical analysis produced the following surprising results:

   > There were no effects of any of the fat types on overall incidence of prostate cancer.
   > When looking at the high-grade form of prostate cancer that progresses rapidly and is the most lethal:

• Those men with the highest blood levels of DHA from fish oil had more than twice the risk of contracting high-grade prostate cancer as men with the lowest blood levels of DHA.
• EPA from fish oil had no effect on the incidence of high-grade prostate cancer.
• Those men with the highest blood levels of trans-fats had about half the risk of contracting high-grade prostate cancer as men with the lowest blood levels of trans-fats
• Blood levels of the type of omega-3 fat from vegetable sources (e.g. flax seeds, walnuts) had no effect on the incidence of high-grade prostate cancer.

Bottom Line
The results of highly surprising, given the widespread view of fish oil as all-good and trans-fats as all-bad. Here is a clear case of trade-off. There is considerable evidence that fish-oil is good for the heart and cardiovascular system and reduces the incidence of heart attacks. Yet, here we see that it increases the risk of high-grade prostate cancer. Eating omega-3 fats from flax-seeds or other vegetable sources is not a solution because that type of omega-3 fat has not been proven to reduce the risk of cardiovascular disease. The good news is that most prostate cancer is of the low-grade variety. Given that heart disease remains the number one killer of both men and women, it doesn’t appear that fish and fish-oil be abandoned as a health-promoting dietary elements. Yet men must be aware of the trade-off in risk of eating fatty fish or taking fish-oil supplements in order to make an informed decision about how best to promote their health.

Update (May 8, 2011):
Consumerlab.com, a company that tests the quality of supplements from various companies, contacted Dr. Theodore Brasky, the lead author of the study described herein. He stated that the blood levels of DHA and EPA measured in the study were largely based on fish consumption rather than fish-oil supplements. However, a recent study of his, soon to be published, shows no link between fish oil supplementation and risk of prostate cancer. He also noted another study (Szymanski, Am J Clin Nutr 2010) that found fish consumption associated with a large reduction in late state or fatal prostate cancer.

Soy Products Have a Negative Effect on Masculinity

Because it is a relatively inexpensive source of protein, soy is widely used to fortify many high-protein foods such as bars, cereals and shakes. However, as detailed on our website, the estrogen-like qualities of soy proteins (isoflavones) have a negative effect on masculinity.

A recent study by Wada et al. in the American Journal of Epidemiology (vol. 173, no. 9, pp. 998-1003, 2011) indicates that such demasculinizing effects can begin very early. The researchers collected dietary histories and urinary testosterone levels from 230 Japanese boys aged 3-6 years. When the boys were divided into 4 groups based on the quantity of soy they ate, the group that consumed the least soy had a notably mean higher testosterone level than the other 3 groups. The same was true when the grouping was made based on isoflavone consumption.

The American Academy of Pediatrics, but not the U.S. government, has recommended that infants who cannot be breastfed be nourished with formula based on cow milk rather than soy. Also, several countries including Israel, France, New Zealand, and Australia have officially recommended against soy-based baby formula. While the U.S. has made no such official recommendation, parents here would do best to avoid soy-based infant formula as well as soy-containing foods for their older children.

Bottom Line
Men should carefully read nutrition labels and avoid foods containing soy or isolated soy protein. Preferable sources of protein include fish and lean meats, low-fat dairy products, and eggs in moderation. Acceptable protein supplements include whey protein and casein, both derived from milk. Some men avoid milk because they believe they are intolerant of lactose (milk sugar). Yet many of these men are not actually lactose intolerant. For those who really are, there are many alternatives. Whey protein and casein do not contain lactose, and have shown in studies to be very effective for muscle building. Most cheeses are made up mainly of protein and fat, with very little lactose, but should be eaten in moderation because of the high saturated fat and cholesterol content. Milk products should be of the low-fat or non-fat varieties to limit saturated fat and cholesterol. Lactose-free milk is also available in most supermarkets.

Our Changing Eating Patterns

The U.S. Department of Agriculture recently published information on the sources of our daily caloric intake between 1970 and 2008, a time period in which our daily caloric consumption increased by 23.2% from 2,169 cals to 2,672 cals, and rates of overweight and obesity have risen sharply. An interactive graphic was created from the data that allows users to scroll along a time-line to see how the amount of daily calories in each food category has changed over time. The following are the percentage changes in calories coming from each food category:

meat, eggs, and nuts: +4.1%
fruit:                         +22.9%
added fat:                 +56.3%
dairy:                          -3.7%
grains:                      +44.7%
vegetables                   -2.4%
added sugar              +14.2%

Some Observations on the Data

In Terms of Absolute Calories

• The biggest contributors by far to our increased daily caloric intake are added fat (231 cals) and grains (193 cals).
• Much more modest contributors to our increased daily caloric intake are added sugar (57 cals), meat/eggs/nuts (19 cals), and fruit (16 calories).
• Our daily consumption of dairy actually decreased by 10 calories and of vegetables by 3 calories.

In Terms of Percentage of Daily Calories

• The only foods that increased as percentages of our diet from 1970 to 2008 are added fats (from 18.9% to 24.0% of daily calories) and grains (from 19.9 % to 23.4% of daily calories).
• Caloric consumption from fruit was steady at 3.2 % of calories.
• All other foods declined as percentages of our daily calories including meat/nuts/eggs (from 21.3% to 18.0% of daily calories), dairy (from 12.3% to 9.6% of daily calories), added sugar (from 18.5% to 17.2% of daily calories), and vegetables (from 5.8% to 4.6% of daily calories).

Bottom Line
The greatest contributors to our increase in caloric consumption are grains and added fat. While we have increased our intake of all other foods except vegetables, grains and fat together account for 84% of our increase in caloric consumption and should therefore be the prime focus of cutting back calories. This makes it clear that the low-fat and low-carb diets are both missing something because the intake of both must be reduced. Any diet that emphasizes what you eat rather than how much you eat is bound to fail. Overweight and obese people who seek to attain a healthy body weight must face the reality that total intake must be lessened. Focusing on eating both fewer grain-based foods and fewer added fats is a good start.

Can Video Games Improve Physical Fitness?

With the development of video game devices that detect body motions of players and use those motions to control games, the opportunity for turning the formerly sedentary activity of video gaming into physically active fun has greatly expanded. However, it is only recently that the exercise stimulus of such games has been scientifically evaluated. One such study, by Worley, Rogers, and Kraemer was recently reported in the Journal of Strength and Conditioning Research (vol. 25, no. 3, pp. 689-693, 2011).

Experimental Procedure
8 young women averaging 22 years of age were first tested for the maximal rate at which their bodies could process oxygen (VO2max). Then they played 2 different Nintendo Wii Fit video games (Hula and Step) at the beginner and intermediate levels for 10 minutes each. During each game session, each subject was connected to a metabolic cart that measured the rate of oxygen consumption.

Results
The percentage of VO2max elicited during the video games ranged from 30.6% for the beginner level Step game to 39.4% for the intermediate level Hula game. These levels respectively corresponded to walking speeds of 2.5 mph and 3.6 mph, categorized as mild to moderate exercise.

Bottom Line
Video games that require physical activity have excellent potential for getting people who would not ordinarily exercise to do so. Nintendo’s Wii system involves a controller that is held in the hand and picks up movements using accelerometers. The XBOX game with the Kinect accessory is revolutionary in that it senses whole body movements without anything held in the hand or attached to the body. While the games in this study only elicited mild to moderate levels of exercise, the advanced game levels were not tested, probably because they require a lot of practice. Thus, the potential for higher exercise levels is certainly there. These games are a great way of getting people who are not attracted to sports or typical exercise routines but who like video games to become more physically active.

Effectiveness of Different Kinds of Strength Training Periodization

Periodization of strength training entails changing over time the weight handled in each exercise along with the number of repetitions per set. When the weight used is higher, the number of repetitions is lower and when the weight used is lower, the number of repetitions is higher. It is widely agreed among strength and conditioning professionals that periodized strength training is more effective than non-periodized training.

There are various versions of strength training periodization, including:

• Traditional periodization - The trainee starts with relative light weights and high repetitions, and over a period of several weeks, increases the amount of weight lifted while decreasing the number of repetitions. For example, the trainee might begin by doing 10 repetitions per set with 60% of the maximum weight that can be lifted for a single repetition and progress to 4 repetitions with 80% of the max weight.
• Daily Undulating Periodization - On different days, the trainee uses a different combination of weights and repetitions. A sample schedule might be medium weight and medium reps on Monday, light weight and high reps on Wednesday, and heavy weight and low reps on Friday.
• Weekly Undulating Periodization - Weight and reps fluctuate from week to week. A sample schedule might be low weight and high reps on week 1, medium weight and medium reps on week 2, and high weight and low reps on week 3, with this 3-week pattern repeating several times.

A recent study by Apel, Lacey, and Kell in the Journal of Strength and Conditioning Research (vol. 25, no. 3, pp. 694-703, 2011) sought to determine the relative effectiveness of traditional vs. weekly undulating periodization.

Experimental Procedure
Forty-two young, physically active men were divided into three groups of 14 that trained for 12 weeks as follows:

• Control group - Performed no strength training
• Traditional periodization (TP) - Increased the resistance in a fairly linear manner from 57% of max the first week to 80% of max the final week.
• Weekly Undulating Periodization (WUP) - Started at 57% of max, but increased resistance over 3 weeks before reducing weight close to where it started and increasing it back again over 3 weeks. This was done over 3 cycles in which both the starting and ending weight for each 3-week cycle became greater than for the previous 3-week cycle, ending at 78% of max.

There were 15 different exercises selected to work the entire body. The exercises used, rest time, total exercise volume and average percent of maximum weight used were the same in both groups. There were 3 training sessions per week for the first 2 weeks and 4 per week for the remaining weeks, in which half the exercises were performed 2 days per week (e.g. Mon. and Thu.) and the other half on 2 other days per week (e.g. Tue. and Fri).

Results

• Both periodized training groups increased significantly in strength, while the control group did not.
• Increases in back squat strength were significantly greater for the TP group (54%) than for the WUP group (34%).
• Increases in bench press strength were significantly greater for the TP group (24%) than for the WUP group (19%).
• Increases in pull-down strength were significantly greater for the TP group (29%) than for the WUP group (19%).
• Increases in dumbbell shoulder press strength were significantly greater for the TP group (48%) than for the WUP group (36%).
• Increases in leg extension strength were greater for the TP group (39%) than for the WUP group (27%), although the between-group difference did not reach statistical significance.
• There was more muscle soreness and fatigue reported among the WUD group, which may have hindered training progress.

Bottom Line
For this group of recreationally active males, traditional periodization produced superior results to weekly undulating periodization. The between-group differences were great enough to be meaningful.

Is Cycling Actually Detrimental to Bone Health?

An article by Nichols and Rauh in the Journal of Strength and Conditioning Research (vol. 25, no. 3, March, pp. 727-734, 2011) showed that hours of weekly bicycling exercise, in the absence of weight-resisted or impact exercise may actually be worse for bone density than no exercise at all. While such exercise seems fine for keeping the heart, lungs, and circulatory system healthy, and bodyweight under control, the evidence shows that it is a poor exercise for bone health.

Experimental Procedure
The study tracked, over a 7-year period, bone density in the lumbar spine, total hip, and femoral neck (segment of the thigh bone adjacent to the pelvis) as well as body fat and lean tissue measurements of 19 Master’s competitive cyclists and 18 non-athletes, who averaged 51 years of age at the start of the study.

Results

• At both the initial and final testing, the cyclists had consistently lower bone mineral density at all sites measured than the non-athletes.
• After statistical adjustment for changes in body mass index, lean mass, calcium intake and exercise habits, the cyclists lost more bone mineral density over the 7 years than the non-athletes.
• The subjects who reported doing weight-bearing or impact exercise lost significantly less bone density in the spine and femoral neck than those who did not do such exercise.
• At initial testing, 84% of the cyclists and 50% of the non-athletes met the criterion for osteopenia (subnormal bone density).
• At the final testing, 90% of the cyclists and 61% of the non-athletes met the criterion for osteopenia.
• Six of the cyclists but only one of the non-athletes had full-blown osteoporosis (critically low bone-density) by the end of the study.
• Even when they were made aware of bone-density problems, very few of the subjects changed their diets to include more calcium.

Bottom Line
The evidence provides a strong indication that cycling is not beneficial to bone health. If done in the absence of weight-resisted exercise (e.g. squat, deadlift) or impact exercise (e.g. running, gymnastics, dance) bone loss is likely to result. One hypothesis is that the lack of impact or weight on the bone fails to stimulate mineralization, while calcium-containing sweat is lost during heavy cycling exercise. Another possibility is that endurance exercise tends to suppress testosterone, which helps maintain bone mass. Older competitive cyclists are at great risk for bone fracture because of their low bone density and high risk of bicycle crashes. Weight-resisted or impact exercise should be started when people are young because that is when bone is most readily mineralized.