Yesterday I decided it would be a good idea to climb one of the tallest mountains I could reach on public transportation, without having gone hiking in months. Needless to say, I am wiped out. I still want to do some sort of workout, but I have no idea what I can handle. Here are some great ideas for working out when you are far too tired to actually workout: 1. Why you're tired: You've been sitting all day. What to try: A short high-intensity interval workout (HIIT -- for example, all-out cycling bouts for 30 seconds, followed by 4 minutes of rest, repeated 8 times). These types of short HIIT routines can increase the feeling of vitality without tiring us out the way longer workouts might. 2. Why you're tired: You've been working out too much. What to try: Do something easy that gets you going, but not so much that it makes you sweat or pant: Play Frisbee with your kids or dog, take an easy yoga class or ride your bike to the movies. Overtraining is caused by a lack of recovery time, and it can put you at risk of injury. Light, relaxing exercise is much more beneficial than any day of vegging out. 3. Why you're tired: You didn't get to bed until 3:00 a.m. What to try: Skip your workout. Go to sleep. If you didn't get enough rest last night, a 20-minute afternoon nap can help you get through the day. Getting a full seven to eight hours tonight will help you feel better tomorrow -- strong enough to rock any workout you choose.