An early-morning workout can blast the cobwebs away.
But if you really want to feel the benefits of exercise, it might be better to wait until the afternoon.
That, according to scientists, is the best time to put muscles and stamina to the test.
Thanks to studies of the body's natural rhythms, they say they can pinpoint the best times for working up a sweat, enjoying a drink, using some serious brainpower or even making love.
To get the best out of your day, they suggest working or studying in the morning and putting off any physical exercise until mid to late afternoon.
Circadian rhythms
Russell Foster, a professor of molecular biology at Imperial College London, said doing things the other way around inevitably results in poorer performance.
This is because hormones are highly active in the morning, helping to boost concentration and short-term memory, while body temperature - which maximises muscle performance - only peaks between 5 and 6pm.
If your typical daytime schedule does not match up to the expert advice, you may fare better in the evening.
The best time to enjoy a drink for example, is between 7 and 8pm - just as the pubs start to fill up.
It also happens to be the time when the liver is at its most active in detoxifying the body.
Libido tends to peak between 10pm and 1am, meaning the best time to make love helpfully coincides with most of our bedtimes, said Professor Foster.
According to the research, ovulation typically occurs at midnight which means late at night is also the best time to conceive.
The guidance is based on circadian rhythms - fluctuations in the body's needs and capabilities which repeat roughly every 24 hours, dictated by the cycle of night and day.
"We cannot yet explain some of these things, but over a 24-hour period there are constant changes in light and temperature which the body responds to and also prepares itself for," said Professor Foster.
"It's ironic that so many people go to the gym in the morning and that Olympic athletes will get up at 4am to train because the difference between performance then and the potential later in the day is huge."
Peaks and troughs
In the U.S., researchers found lung function was at its worst around midday and its best between 4pm and 5pm - providing another reason to exercise in late afternoon.
But if it is your brain that needs a workout, then late morning is the best time to knuckle down to some serious concentration.
Levels of cortisol - a hormone related to stress but which can help mind function - rise rapidly between 6 and 8am as the body prepares for the day ahead.
But early-morning sleepiness can still be taking its toll at this time of day.
It is not until 10 or 11am - at which point heart rate and blood pressure have also 'warmed up' - that the ability to concentrate and solve problems is at its peak.
"Hormone levels are high in the morning and there is some evidence that they can enhance mental performance," said Professor Foster.
"If you are doing an exam, ideally you should start at 11am and finish at 1pm and that would probably put you at a statistical advantage over people doing it in the afternoon."
However, he was less certain about the peaks and troughs of libido. The fact that it tends to peak in the late evening could also be due to cultural reasons, he said.
"A cynic might say that it's simply because that's when the pubs turn out," he added.
"It is certainly a distinct rhythm in terms of libido, but whether it is for social reasons or it is driven by our biological clock, we don't know."
Making the most of time
A better understanding of the body's rhythms could do more than simply help us make the most of our time.
Scientists believe it could also be used to work out the most effective times to take medication.
For example, the discovery that lung function is strongest in the afternoon could mean asthma treatments are more effective even in small doses at this time of day.
But not everyone can benefit from the body rhythm boom. Shift workers appear to be beyond help.
"Between 4am and 6am, your ability to do manual tasks is impaired in the same way as if you were drunk," said Professor Foster.
"Even if you work night shifts for 20 years, that doesn't change."
Read more: http://www.dailymail.co.uk/health/article-324555/The-best-time-work-rest-play.html#ixzz1bI7GbLo1