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”.