Over the years, my exercise regimen has steadily evolved ~ standard calisthenics in high school ~ boxing, fencing and swimming at my first university ~ the Army's daily dozen ~ bicycling and jogging ~ karate and weight training at my second university ~ and more recently a daily 40-minute physical therapy workout culled from exercises for sprained ankles, a separated shoulder, elbow-shoulder-ankle tendonitis, arthritis, and a herniated lumbar disk, injuries which I've accumulated over a long and active life.
While the current PT routine keeps me limber (I can once more do the Plow position, and can touch my toes without bending my knees), it does little to further cardiovascular fitness or to build up muscle mass.
With this in mind, my attention was piqued by a NYTimes article which summarizes a 7-minute daily workout developed by two sports training professionals at the American College of Sports Medicine. Their workout compresses a normal fitness routine (extended weight and cardio exercise) into 12 exercises organized in a sequence which alternates among all major muscle groups, with 30 seconds devoted to each exercise, interspersed with 10-second recovery intervals. The routine can be performed one or several times per day, and requires no special equipment beyond a chair, a wall, and one's own body weight.
I highly recommend reading the original ACSM article for a more complete understanding of the research, methods, and goals of the workout. Below is a description with illustrations (courtesy of the ACSM website) of a sample 12-station HICT (high intensity circuit training) program.
"The exercise order allows for a total body exercise to significantly increase the heart rate while the lower, upper, and core exercises function to maintain the increased heart rate while developing strength. Exercises are performed for 30 seconds, with 10 seconds of transition time between bouts. Total time for the entire circuit workout is approximately 7 minutes." (Click on any image to enlarge. The entire circuit is depicted above, and individual exercises are shown below.)
Jumping jacks ~ total body
Wall sit ~ lower body
Push-ups ~ upper body
Abdominal crunch ~ core
Step-up onto chair ~ total body
Squat ~ lower body
Triceps dip on chair ~ upper body
Plank ~ core
High knees/running in place ~ total body
Lunge ~ lower body
Push-up and rotation ~ upper body
Side plank ~ core
Caution ~ unless you already exercise daily, it is advisable to consult your doctor before starting a new fitness program. Monitor your breathing and pulse initially. With practice you'll be able to judge how hard to push, bearing in mind that the target is a sustained elevated pulse rate during the entire circuit. Good luck, and have fun!