You probably didn’t start a new fitness routine just for your health. You want to see results, whether that means gains in strength, bigger muscles, or greater endurance.
But exactly how much time do you need to put in, per session and per week, before you can tell it’s working?
In fact, they shouldn’t be, unless you’re actually training for a marathon or other long endurance event. For goals of strength, hypertrophy (muscle growth), athletic speed, and general fitness, there’s a point of diminishing returns in terms of session length. “Perhaps the biggest misconception, when it comes to training, is ‘more is better,’” says Greg Justice, M.A., personal trainer and founder of Kansas City’s AYC Health and Fitness. “I personally prefer 30- to 45-minute sessions as the naturally increased testosterone levels in your body peak somewhere around the half-hour mark of your training session. At the 45-minute mark, your testosterone levels are trending back to baseline.” If you go longer, your body will begin to produce more cortisol (stress hormone) and less testosterone—counterproductive to any gains you made.
“To create the mechanical and metabolic overload for growth, a workout that has high intensity (heavy weights or explosive speed of movement) only needs to be done for 2 to 5 reps and 3 to 6 sets with at least 2 minutes of rest between sets,” says Pete McCall, M.S., C.S.C.S., a strength coach and fitness educator based in San Diego. On light days—which you should have, because they facilitate recovery—you’ll go a little longer, thanks to the higher rep ranges. And there should be a minimum of 48 hours between high-intensity sessions, as well as many good nights of sleep, to optimize results.
For most goals, three to four total-body workouts a week is plenty, especially if you’re just starting a new program. “After the first four to six months of training, it might be necessary to do four to six sessions per week week to keep adding stimulus to the muscles,” McCall says, in the form of body-part splits. If your goals are cardio-based, three 30-minute sessions at a moderate intensity will elicit improvement. “As an individual’s cardiovascular endurance improves, they can then progressively increase the amount of sessions per week as well as the intensity, distance or time of each session,” says Justin Smith, a San Diego personal trainer and health coach.
...in as little as a month, particularly if you haven’t training (or trained in this manner) in a while. In terms of strength training, you could see a 10% increase in what you can lift each month for the first four to six months, McCall says, at which point the adaptations will slow and you’ll have to change up your workouts to keep ‘em going. For hypertrophy, noticeable results might take a little longer—four to eight weeks of targeted training—with seriously tape-measurable results in four to six months.
“A beginner can see as much as 2 1/2 pounds of muscle per month, but that will level out with more experience,” Justice says, though the scale may not show it as this doesn’t account for any fat loss you may also experience. Cardio changes happen pretty quickly, too, especially at first.
In a few weeks, you might notice you’re less winded when you climb the stairs or run for the train. If you’re curious to see exactly how your heart and lungs are adapting, you can get your VO2max measured in a lab at the beginning of your program and again after some weeks of training. Or try this (free) gauge: Run a mile on a track at the beginning of your program and every month and record your times.