Exercise prescriptions first started in 1968 when Ken Cooper recommended that everyone amass 40 points a week to achieve aerobic fitness. For example, this could be achieved by running one eight-minute mile a day, five days a week. Cooper’s recommendations worked for a few, but were based upon research with young air force servicemen, not exactly a representation of the American population. Older people and women were ignored. In an effort to prescribe exercise specific to individuals, the American College of Sports Medicine (ACSM) recommended 15-60 minutes a day at 60% VO2max or 60% of max heart rate reserve. This didn’t work either because people didn’t know their VO2max or their max heart rate reserve. Many people who could not work continuously for 15 minutes quit, figuring it wasn’t worth it.

We continue to be inundated by various recommendations, some good, some silly. Since many people have reported that they don’t have enough time to exercise, researchers worked to find the shortest time necessary to develop aerobic fitness. High intensity interval training (HIIT) was born, finding that 4-5 minutes of HIIT worked. Personal trainers developed interval workouts for their clients, but they had not read the original research. The real HIIT, as developed in the laboratory, is brutal, an effective workout if you don’t mind throwing up. If you’re looking for a pleasant aerobic workout, HIIT is not for you.

ACSM’s current recommendation, “Perform moderate intensity aerobic activity for a minimum of 30 minutes, five times per week OR vigorous intensity aerobic activity for a minimum of 20 minutes, three times per week,” is reasonable and understandable. We need to understand that this is just a recommendation, not a mandate. Basically, you don’t have to do all the exercise at once. All exercise helps, whether it is 30 minutes or less.

Most earlier recommendations did not mention strength, presuming that the heart was our only important muscle. The current ACSM recommendation suggests resistance exercises for the major muscle groups twice a week. So now we have a decent recommendation for aerobic fitness and strength but is that enough? Let’s say you do your 30 minute exercise session; what do you do for the other 23.5 hours? Sit? I’ve written that technology has robbed us of the need to move. Even if you complete your 30 minute exercise session, extensive sitting will be your downfall.

Exercise prescriptions do not fit all of our needs. Have you ever noticed that almost every exercise we do is only in one direction — one plane — forward/backward? Running, walking, swimming, rowing, and cycling are all done in one plane. Even exercises in the weight room are either forward or backward. Meanwhile, we live in a 360 degree world that requires a wide variety of movements — we need mobility. Strength, coordination, balance, stamina, and flexibility are all part of mobility, one key to independent living. We know that playing games requires us to change directions. Racket sports, basketball, and volleyball are great additions. Golf, fishing, kayaking, bowling, and dancing also require their own movements. Simple activities like shooting a basketball or playing catch enhances our ability to move.

Be creative; test yourself. Can you get up off the floor without pushing on something with your hands, can you sit cross legged? Can you balance on one leg for 10 seconds, 20? Can you skip? Can you carry your suitcase, climb into a kayak, carry your groceries, squat down to pick up something off the floor? Mobility promotes independence. Floor exercises help and require no equipment. Floor exercises require you to get up and down. Do this repeatedly. Lie on your back and do single leg lifts, bend your knees and lift your hips. Stand up, practice balancing, do squats and lunges.

Think of the world as your gym, not just the track or the weight room Stairs are just a cheap StairMaster. You can find exercise everywhere. As one story goes, a man gets in his car and fights two miles of traffic to work. He circles the lot, looking for a spot close to the entrance, takes the elevator to the third floor. After work he drives to the gym, gets on an indoor cycle and performs the 30 minute ritual. He leaves the gym, drives two miles home to pay the guy who just mowed his lawn. His son is shooting baskets in the driveway and asks dad to join. “Sorry, I already worked out today.”

Jim Johnson is a retired professor of exercise and sport science after teaching 52 years at Smith College and Washington University in St. Louis. He comments about sport, exercise, and sports medicine. He can be reached at jjohnson@smith.edu