Since the beginning of the modern fitness boom four decades ago, our workouts have been neatly packaged into 60 minutes. The only reason for this exact length of time is because it looks nice on paper. Everything on our daily timetable is an hour, and workouts slide right in amongst meetings, dentist appointments, and kids' soccer practices. It's not because 60 minutes is a good length of time for an exercise session. In fact, shorter workouts are better for burning calories, strengthening muscles, and overall morale.
At the end of a regular hour-long workout, ask yourself, "Could I have worked harder for less time?" Try upping the intensity a few notches and exercise for 45 minutes instead. Give yourself a kick in the caboose such that at 45 minutes you think, "Whew, glad that's over. Couldn't do another minute." But watch out... increased intensity and ripping-muscles-to-shreds are not the same thing. Your workouts should be appropriately difficult.
Traditional, steady-state workouts - brisk walking, jogging, cycling, etc. - can go on for hours. On an exertion scale of 1 to 10, you hang out at a moderately intense 6, maybe 7. This is okay, certainly better than the sofa. It's definitely the entry point for those new to exercise. The health benefits of all physical activity are worth every minute of time invested. However, interval training is your means to shorter workouts and an amplified fitness level. And who couldn't use a few extra minutes in the day? An interval is an effortful bout of perhaps 20-60 seconds where you attain a perceived exertion of 9 or 10. It feels yucky (to put it nicely), but you hang in there because it's quick.
Here's the science behind it all. Each person is made up of approximately 50% slow twitch and 50% fast twitch muscle fibres. Some people might have more of one or the other, but on average it's 50/50. Right now as you're reading this article, even if you're reading it on a stationary recumbent bike, your slow twitch fibres are meeting all of your steady-state muscle contraction needs. Fast twitch fibres, built for powerful, explosive movements, take over only when slow twitch fibres can't do the job. Let's say you're reading this article in your basement, and the phone rings. You're expecting a very important phone call. The handset of the phone is at the top story of your house. You immediately bound up two flights of stairs and answer with a breathless, "Hello?" You've just tapped into your fast twitch muscle fibres.
Without intervals, you only ever employ 50% of your body's potential, regardless if your workout is 60 minutes or 120 minutes. Translation, fitness level plateau, decreased results, sunken motivation, and cancelled gym membership. Take note: You can't shorten your workout time and keep the same pace you always have. Appropriate intensity is key. It's a zone, and the zone is different for everyone. The zone changes as your fitness level changes. 'Effective' is the lower zone criterion. Was your workout worth lacing up for? Was it challenging enough to elicit results? 'Safe' and 'Successful' are the upper zone criteria. If you push too hard, you could get discouraged or, worse, injured. Both too little or too much are counterproductive.
Here's the plan. Get out of the low-motivation 60-minute rut. Have shorter, more intense, invigorating workouts most days of the week. And when you're not exercising, stay active. Walk to your meeting, or better yet, forget the meeting and get into nature. Ride your bike to the dentist and your child's soccer practice. Keep your phone handset on the second level of your stairs, ready for an explosive burst of leg muscle power at any time.