Both exercise and sunlight have a direct impact on your sleep system and your body temperature rhythm. If you don’t get sufficient exercise and sunlight, you increase daytime drowsiness because you inhibit the daily rise and fall of body temperature.
When feeling drowsy and lacking energy during the day most people quickly jump to the conclusion that it is because they didn’t get enough sleep. For this very reason, they rest more and decrease their activity level based on the theory that “I’m feeling tired, so obviously I didn’t get enough sleep last night and I should probably get some rest.”
This is a faulty theory and exactly the sort of behavior that will only create additional sleep problems for you! It is counterproductive because by being inactive and staying indoors you are flattening your body temperature curve so you will feel more tired when in fact you are supposed to be feeling awake. You can easily get caught in a vicious cycle: the more fatigue you encounter, the more you are likely to stay inactive (and consequently the less restorative your sleep will be at night). You are also more likely to stay indoors and thereby limit your exposure to sunlight.
Also, keep in mind you can perform on less sleep than you think! In addition, for a brief period you can perform with less sleep than you need, so discard that particular worry for now. Although you may get less sleep than you need on occasion, the proper way to combat this reality is by being physically active and staying outdoors in order to receive exposure to natural light! Go get up, get out and get active!
When you’re feeling tired, fatigued and lacking in energy you are likely to try to compensate for this by getting to bed early. Unfortunately, this only weakens your sleep system by decreasing your prior wakefulness, which decreases your “sleep drive.”
You will also tend to decrease activity levels and your exposure to natural light by going to bed early. Remember the goal is just the opposite: you want to increase prior wakefulness to create a deeper, restorative sleep. By doing the opposite you will only encourage lighter and less rejuvenating sleep which leaves you feeling drowsy and without energy during the day. This, in turn leaves you with a tendency to be inactive and stay indoors, and the vicious cycle continues!
Remember! Even if you did in fact get too little sleep, the best way to counter a sense of tiredness, fatigue and lack of energy is by getting sunlight and exercise and not by staying inactive and resting. This will only trap you further in this cycle!
No matter how little you sleep or how little you think you have slept or how drowsy you feel - get out and get active! This is the best way to turn this vicious cycle around: incorporate an element of daily outdoor activity into your life!