On this episode of Dr. Marla & friends:

It is believed that nearly a third of Canadian kids are overweight or obese. We meet one mother who went to great lengths to help her son deal with his weight issues.

Concerned about Alzheimer's? Dr. Ron Keren outlines key risk factors and some prevention tips.

And in this week's panel discussion, do you really need eight hours of sleep? The answer might surprise you.

Digital Extra: Tips to getting a good night's sleep

We’ve long been taught that humans need eight hours of sleep to feel well-rested. But the truth is that number doesn’t apply to everyone and certainly not for their whole lives.

“Sleep needs are completely variable so it’s a bit of a magical number that causes a lot of problems, because people become a little obsessed with it,” sleep expert and Ryerson University psychology professor Dr. Colleen Carney, tells Dr. Marla & Friends.

“Some people are six-hour sleepers and they’re healthy sleepers. Some are nine-hour sleepers and they’re healthy sleepers. It changes with individuals and it changes even over time.”

Dr. Colin Shapiro director of UHN’s Sleep and Alertness Clinic in Toronto says, as people get into middle age and older, the quality of their sleep will change.

So, while teenagers might get 20 or 25 per cent deep sleep, those in their 50s get only about 10 per cent while those in their 70s get about five per cent, leading to more breaks in their sleep.

There can be a lot of things that reduce the quality of our sleep, such as too much light in the bedroom, too much caffeine, or working shift work. But sometimes we just spend too much time in bed because we think we need more sleep, says Carney.

“If our sleep need is shrinking but we’re trying to spend the same amount of time in bed, then we’re artificially going to create some insomnia because we only have a certain amount of sleep debt built up,” she says.

Shapiro says there are ways to improve the quality of one’s sleep, so that we can eventually spend less time sleeping.

Here are 12 tips from Harvard Medical School's Department of Sleep Medicine to improve your sleep:

1.  Manage your intake of caffeine, alcohol and nicotine

Avoid caffeine in coffee, tea, chocolate, cola, and some pain relievers for four to six hours before bedtime.

Similarly, smokers should refrain from using tobacco products too close to bedtime.

Alcohol will increase the number of awakenings and decrease the quality of sleep later in the night. So limit alcohol to one to two drinks per day, and avoid drinking within three hours of bedtime.

2. Turn your bedroom into a sleep-inducing environment

A quiet, dark, and cool environment can help promote sound slumber. Use heavy curtains or blackout shades to block light, which otherwise serves as a powerful cue that tells the brain it's time to wake up.

Keep the temperature comfortably cool—between 16 and 22 degrees Celsius (60 and 75 degrees Fahrenheit) -- and the room well ventilated.

And make sure you have a comfortable mattress that's less than 10 years old.

3. Establish a pre-sleep routine

Light reading before bed is a good way to prepare yourself for sleep.

Avoid stressful, stimulating activities before bed, because they can cause the body to secrete the stress hormone cortisol, which is associated with increasing alertness.

4. Go to bed only when you’re truly tired

Struggling to fall sleep just leads to frustration. If you’re not asleep after 20 minutes, get out of bed, go to another room, and do something relaxing, like reading or listening to music until you are tired enough to sleep.

If you wake up in the middle of the night and can’t get back to sleep in about 20 minutes, get up and engage in a quiet, restful activity such as reading or listening to music but keep the lights dim.

5. Don’t be a nighttime clock-watcher

Staring at a clock in your bedroom, either when you are trying to fall asleep or when you wake in the middle of the night, can actually increase stress, making it harder to fall asleep. Turn your clock’s face away from you.

6. Use light to your advantage

Natural light keeps your internal clock on a healthy sleep-wake cycle. So let in the light first thing in the morning and get out of the office for a sun break during the day.

7. Keep a consistent sleep schedule

Going to bed and waking up at the same time each day sets the body’s "internal clock" to expect sleep at a certain time night after night. Try to stick as closely as possible to your routine even on weekends to avoid a Monday morning sleep hangover.

8. Nap early -- or not at all

Many people make naps a regular part of their day. However, for those having trouble staying asleep through the night, afternoon napping may be a culprit. If you must nap, keep it short and before 5 p.m.

9. Lighten up on evening meals

Finish dinner several hours before bedtime and avoid foods that cause indigestion.

10. Balance fluid intake

Drink enough fluid at night to keep from waking up thirsty—but not so much that you will be awakened by the need for a trip to the bathroom.

11. Exercise, but do it early in the day

Exercise helps promote restful sleep if it is done several hours before you go to bed.

Try to finish exercising at least three hours before bed or work out earlier in the day.

12. See a doctor if needed

If your sleep difficulties don’t improve through good “sleep hygiene”, consult your physician or a sleep specialist. You could have a sleep disorder such as apnea, restless legs syndrome, narcolepsy, or another clinical sleep problem.