Tuesday, October 18, 2011

Battling Jet Lag

People who travel long distances east or west often suffer grogginess and disorientation resulting from the body’s internal clock being out of synch with the sun. The body’s circadian clock is slightly longer than 24 hours but is synchronized by various environmental factors, the most important of which is light exposure. Jet-lag occurs when the intrinsic clock cannot adjust fast enough.

Westward travel is easier since it require setting the internal clock later rather than earlier. The more time zones that are crossed, the longer lasting and more severe are the symptoms. We can move our internal clock later by 2 hours per day, but can move it earlier by only 1 or1 ½ hours. Light exposure is of primary importance in shifting the circadian clock.

The core body temperature drops 2 to 3 hours before the usual time of awakening. Exposure to bright light before this minimum will set the internal clock later; exposure to bright light after the temperature minimum sets the clock earlier. People who frequently shift time zones may do better if they remain on their home-based schedule.

Sleeping pills may be helpful in reducing jet-lag insomnia but don’t reduce daytime grogginess. Adverse effects are frequent and may include nausea, vomiting and confusion. People who take caffeine are less sleepy but have more nocturnal sleep complaints. Circadian rhythms are retrained more quickly in people who use daytime caffeine.

Jet lag can be minimized by a good sleep environment as well as strategic avoidance and exposure to light. If feasible, remaining on the home-based scheduled will minimize symptoms.

For information on a Jet Lag Plan

Wednesday, October 12, 2011

Economic Aspects of Obesity

In 2000, a French magazine proclaimed that “America is just a huge eating machine.” We Americans are becoming more obese; a conference in 2008 discussed the effect on individual behavior of issues such as food prices, wages and access to fast food. The papers presented at that conference are compiled in Economic Aspects of Obesity, edited by Michael Grossman and Naci Mocan (University of Chicago Press).

There are clear-cut economic causes and consequences of obesity, and individuals struggling to shed excess weight face enormous difficulties. Weight loss strategies are regularly announced – many are difficult to comprehend and conflict with previous pronouncements. Mike Luckovich published a cartoon in which a woman declares, “Finally, an understandable food pyramid,” looking at one that says “Eat less.” Not so easy – the television commercials are every more enticing and the Starbucks beverages are approaching Slurpee size.

For the entire book: Economic Aspects of Obesity

Why you get hungry watching television: Tabletop Directors

How many calories in the largest Slurpee? Almost 400. Nutritional value: Almost 0.

Tuesday, October 4, 2011


The primary prevention of cardiovascular disease consists of treating patients with elevated lipids before a heart attack or stroke. This might seem obvious at first glance, but the evidence that lowering cholesterol will actually prevent a heart attack is inconsistent. Patients with the greatest risk are the ones most likely to benefit from medication and statins are the medications that have the most convincing data.

Pharmaceutical companies have devoted great resources to the development and study of medications to lower cholesterol. It is disappointing that a critical analysis of these studies has failed to show the superiority of statin therapy over life-style changes and aspirin; there is no difference between statins and placebo in all-cause mortality. No particular statin has been shown to be superior at preventing coronary heart disease and at equivalent doses all statins substantially reduce LDL cholesterol (the ‘bad’ cholesterol). Guidelines in the United States, the United Kingdom and Canada agree that lowering LDL l should be the primary target of therapy.

Some patients will still have low levels of HDL cholesterol (the ‘good’ cholesterol) or high level of triglycerides even after meeting their LDL target. There is no good evidence that treating these secondary lipid abnormalities with additional medications will prevent a first heart attack.

Statins will not reduce mortality in patients with peripheral artery disease but will increase maximal walking distance by 499 feet and pain-free walking distance by 295 feet. The rate of expansion of abdominal aortic aneurysms does not change with statin therapy but patients who are taking statins at the time of rupture are more likely to survive.

The bottom line is unchanged: eat a low-fat diet, exercise regularly and stay at a healthy weight. Most importantly: Don’t smoke.

More information: Medicines for Lowering Cholesterol