Morning exercise, green tea can boost your health

04/29/2014 2:41 PM

09/17/2014 3:07 PM

Maintaining a healthy weight and sharp brain are on most to-do lists. And two recent studies provide simple steps to these valuable goals.

Finding time for exercise can be challenging but if you have a choice of when to get outside, go toward the light. A study published this month in PLOS ONE showed that subjects, average age of 30, exposed to the most morning light had the lowest BMI. These 54 volunteers wore a monitor that measured light exposure and sleep patterns, and documented all their food and drink intake.

After studying all the data, the authors concluded the timing of even moderate intensity light exposure is independently associated with BMI. Morning exposure is best and for every hour later, there was a 1.28 unit increase in BMI. Morning light contains more wavelengths in the blue portion of the spectrum, which has the strongest impact on circadian rhythms. The study had limitations in that most subjects had a BMI in the healthy weight range. But the morning clearly has a big upside.

Another study, focused on green tea, was published in Psychopharmacology. Twelve healthy men were given a milk whey-based soft drink containing either 27.5 grams of green tea extract or a similar drink without extract. After the drink was given, via a tube, subjects were given functional MRIs while doing memory tasks. The MRIs showed increased connectivity between parts of the brain and test analysis showed improvement in task performance. The limitations were small study size and use of an extract as opposed to tea. Green tea is loaded with free radical reducing polyphenols. Previous research on green tea has shown it to reduce risk of certain cancers, atherosclerosis and elevated lipids. No downside to enjoying a cup or two of green tea after a morning walk.

About Sheah Rarback

Sheah Rarback


Sheah Rarback, a registered dietitian, is on the faculty of the Miller School of Medicine at the University of Miami. She answers your questions about nutrition.

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