Campbell Craig, exercise physiologist Home Health Rehab, gives his insight into “when should I exercise?”
The past couple of years have seen a rising interest in exercise physiology and the benefits of exercise. Programs such as Insight, Catalyst, and Michael Mosley’s latest self-experiment are helping to shed more light on the seemingly limitless benefits of exercise. Print and digital news media have been highlighting the benefits of strength training to delay or even avoid surgery for arthroscopies and joint replacements! Amazing stuff. I enjoy running 5 different exercise groups each week and after putting people through their paces for 45 minutes we typically spend the final 15 minutes stretching and chatting about my favourite topic, exercise myths. One question that came up this week was “when should I exercise?”
Myth number 1. Do not exercise for 30 minutes after eating
Previously it was believed that you shouldn’t swim for 30 minutes after you ate. Why 30 minutes? Why not 20 or 45 minutes? Why only swimming? I am currently training for a long run which will require me to eat and drink every 20-30 minutes if I am going to have a hope of finishing. To prepare for this, I am not only running until my head torch runs out of batteries (3 times last month), but purposely eating and drinking an uncomfortable amount before heading out the door as this is a way to improve the ability of my stomach to digest and process food and water. I would not encourage this type of behavior to become part of your regular routine, I just want to highlight that there are no hard and fast rules around eating and exercise.
While we are awake, about 25% of the energy we consume goes upstairs to the brain (a very hungry organ). While we sleep, the brains’ energy requirements are only slightly less than during the day and as we are not eating, we rely on the glucose (sugar) stored in our liver to maintain brain function. What this means is that when we wake our brain has depleted our liver and blood sugar supplies; add vigorous exercise on top of this and it is easy to explain feeling light-headed with exertion. Eating prior to exercise helps to avoid light-headed spells by increasing blood sugar levels. There is an art to eating before exercise to maintain your energy levels, however this is really only necessary before long duration or strenuous exercise before breakfast.
Myth number 2. Never exercise before bed
This one might have a little merit. Maybe, possibly, perhaps, IF you find exercise has a stimulating effect and keeps you awake when you are trying to go to sleep. High-intensity exercise (exercise that you cannot sustain indefinitely, but need to break up into shorter bursts) is a simple and effective way to release adrenalin into your system. As we are all unique, the time that it takes for your adrenalin levels to return to normal will vary. Some people may need to avoid high intensity exercise for 2 hours before bed, others may benefit from a rebound-relaxation state where you sleep better following hard exercise. Others might find that they sleep best when they reserve their intense exercise bouts for the morning. What we know for certain is that mild and moderate intensity exercise such as walking, jogging and other continuous forms of exercise do not cause a release of adrenalin and can only benefit a healthy sleep. My final point on this one is that consistent exercise routines contribute to healthier sleeping patterns, while phones, tablets, TV, other stimulating devices, coffee, caffeine, alcohol, stress, working late, smoking, pain, stressful family matters, and depression are all much more likely to contribute to poor sleep patterns.
Myth number 3. You can “spot reduce” fat with exercise
This is probably one of the most common requests that I receive. How can I lose my belly fat? Sit ups? I am going to keep this one simple. Your stomach muscles or ‘abs’ are only a few little muscles, so focusing on them will achieve little results. For big results I recommend taking advantage of big muscle groups such your legs and hips. Let’s look at the numbers. A common recommended goal for weight loss is to increase your exercise by 300 calories each day while reducing your food intake by 300 calories for a 600-calorie deficit, with a net loss of 500g to 1kg per week. In regards to sit ups, if you wanted to burn 300 calories, you would need to perform sit ups for about an hour. Yuck! This doesn’t sound very sustainable. Running and swimming will burn about 300 calories in 30 minutes, while cycling takes about 40 minutes. Walking will also achieve approximately a 300 calorie burn in 60 minutes, but it can be performed in the great outdoors, is associated with a bucket load of other health benefits (significantly reduces back pain and depression to name two), is enjoyable in wintery weather when you are dressed appropriately, and is much more likely to achieve long-term success and therefore help you achieve results. It is also possible to break it up into chunks of 10-15 minutes at a time and build up to 60 minutes or accumulate your 60 minutes throughout the day. Simple.
Fast fact number 1: Exercise aids memory and reduces Alzheimer’s risk
One of the many wonderful effects of exercise is the ability to stimulate your brain, improve your memory, aid concentration, and reduce or delay Alzheimer’s. We used to believe that this was due to improved circulation to the brain with movement, but now attribute improved brain activity to be occurring on a more subconscious level. By simply going for a walk or a run, people are better able to generate ideas, work through problems, or achieve clear thought because the act of regular exercise such as walking is so natural for us that our brain can relax from the task at hand and commit more focused energy to thinking and creativity. For a great visual representation of this, check out this pic of an MRI brain scan (representing brain activity) following quiet sitting and 15 minutes of walking.
Fast fact number 2: Exercise makes you feel good!
The best time for you to exercise is the time that best suits your schedule and lifestyle and can become part of your routine. Once you have established the habit, then that simply becomes what you do, no more thought and anxiety about how or when to fit it in. Life is busy. The more you can make exercise a daily ritual (yes, daily), the less decision fatigue you will have and the more energy you can pour into the rest of your life. Finally, exercise makes you feel good. Exercise stimulates the release of a happy hormone called dopamine, which is also stimulated by taking anti-depressant medications. Exercise is quite literally a happy drug that improves mood and reduces stress levels. Apply liberally for best results.