Tag Archives: fitness

Sleep and Weight Loss

While asleep our metabolic rate increases such that we lose more than three times the amount of weight than if we are awake (awake but lying dormant, of course): 1.9g/min compared to 0.6g/min.

This increase in ‘caloric expenditure’ is not yet fully understood, but there are a number of reasons why we may lose more weight while asleep than awake:

We know that in rapid eye sleep (REM), in which we spend roughly 25% of our total sleep time, the brain’s metabolic rate (the rate at which it consumes energy) is very high, even more than while awake. And while one’s body temperature drops while sleeping, during REM it increases, and this too may cause increased caloric expenditure.

This is in addition to “changes in the hormones which govern hunger and satiety, leptin and ghrelin”.

The Cognitive Importance of Good Sleep

After a week of surviving on minimal sleep you may assume that a lazy weekend will allow you to recover in time for the coming days. Not so: research has shown that not even a full week of quality sleep can reverse the cognitive and physiological ‘damage’ just five days of poor sleep can inflict on us.

Jonah Lehrer notes that it’s not just our cognitive functions that become impaired by a lack of sleep–it’s our immune system, too:

In a recent study for The Archives of Internal Medicine, scientists followed 153 men and women for two weeks, keeping track of their quality and duration of sleep. Then, during a five-day period, they quarantined the subjects and exposed them to cold viruses. Those who slept an average of fewer than seven hours a night, it turned out, were three times as likely to get sick as those who averaged at least eight hours.

Sports Drinks and Dehydration

More for the parents of athletic children, this article from The New York TimesWell blog still contains some useful all-round advice on hydration during exercise. In the comments the author also links to this urine colour test for dehydration.

When [exercising children] were offered grape-flavored water, they voluntarily drank 44.5 percent more than when the water was unflavored. And when the drink included 6 percent carbohydrates and electrolytes — when, in other words, it was a sports drink — they eagerly downed 91 percent more than when offered water alone. Does this mean that parents […] should be stocking their refrigerators with [sports drinks]? The answer is a qualified ‘yes.’ […]

But that ‘yes’ has clear and definable limits. “Sports drinks are only appropriate in the context of sports, and I mean serious sports,” emphasizes Nancy Clark, a registered dietician and sports nutritionist in Boston, who often works with young athletes. If, however, your 12-year-old or older athlete has begun competing at a more intense level, especially if he or she participates in multiple practices or competitions in a single day during the summer, “sports drinks are appropriate,” Clark says.

So not you or I after our daily workout, basically. The article also contains this recipe for making your own sports drink:

1/4 cup sugar
1/4 teaspoon salt
1/4 cup hot water
1/4 cup orange juice
2 tablespoons lemon juice
3 1/2 cups cold water

(Dissolve the sugar and salt in the hot water then add the remaining ingredients. Approx. 50 calories and 110 mg of sodium per 8 ounces.)

via Lifehacker

Alcohol in Moderation: Not So Good, Maybe

Moderate alcohol intake has long been lauded as an ingredient of the healthy lifestyle; being good for your heart and your longevity.

According to a growing number of vocal psychologists, however, studies showing health benefits from moderate alcohol consumption are purely correlatory and any advice coming from them should be taken with caution.

From an epidemiologist at the Centers for Disease Control and Prevention:

The bottom line is there has not been a single study done on moderate alcohol consumption and mortality outcomes that is a ‘gold standard’ kind of study — the kind of randomized controlled clinical trial that we would be required to have in order to approve a new pharmaceutical agent in this country.

[Moderate drinkers and abstainers] are so different that they simply cannot be compared. Moderate drinkers are healthier, wealthier and more educated, and they get better health care, even though they are more likely to smoke. They are even more likely to have all of their teeth, a marker of well-being.

In fact, even the original researcher whose “landmark study [found] that members of the Kaiser Permanente health care plan who drank in moderation were less likely to be hospitalized for heart attacks than abstainers” has since discovered that even moderate alcohol consumption may increase hypertension.

Cognitive Benefits of Exercise

Walter van den Broek (AKA Dr Shock) provides a summary of the research on the neuroscience of exercise, or: the cognitive benefits of an active lifestyle. Exercise…

  • improves learning and intelligence scores.
  • increases the resilience of the brain in later life resulting in a cognitive reserve.
  • [attenuates] the decline of memory, cortex and hippocampus atrophy in aging humans.
  • improves memory and cognition.
  • protects against brain damage caused by stroke.
  • promotes recovery after brain injury.
  • can be an antidepressant.

Reporting on a study conducted at the Neuroplasticity and Behavioral Unit, National Institute on Aging (part of the National Institutes of Health), van den Broek also looks at foods that have been shown to be beneficial for learning (among other brain functions), in addition to providing a bit of neuroscience on how exercise actually “improves the brain”.