The best way to improve and maintain fitness is to combine regular aerobic exercise, strength training, and flexibility work, then stay consistent enough for these habits to stick. That combination covers the three pillars of physical fitness: cardiovascular health, muscular strength, and joint mobility. Getting specific about how much of each you need, and knowing the minimum to maintain your gains, makes the difference between a plan that works and one that fizzles out.
How Much Aerobic Exercise You Need
Current guidelines recommend 150 to 300 minutes per week of moderate-intensity aerobic activity (brisk walking, cycling, swimming) or 75 to 150 minutes of vigorous-intensity activity (running, fast cycling, competitive sports). A mix of both counts too. That works out to roughly 30 minutes of moderate exercise five days a week, which is a manageable starting point for most people.
If your goal is to improve cardiovascular fitness as efficiently as possible, high-intensity interval training delivers more results per minute than steady-state cardio. A Norwegian study compared four training approaches over eight weeks, all matched for total work, and found that interval training at 90 to 95 percent of maximum heart rate improved aerobic capacity by 5.5 to 7.2 percent, significantly more than training at lower intensities. The most effective protocol was four rounds of four-minute hard efforts followed by three minutes of easy recovery, done three times per week.
That said, any form of cardio improves blood pressure, fat metabolism, and insulin sensitivity. Steady-state exercise like jogging or cycling is easier on your joints, simpler to recover from, and still produces meaningful cardiovascular gains. If you enjoy long runs or bike rides, those work well. If you’re short on time, intervals give you more return on investment. The best approach is whichever one you’ll actually do consistently, and many people benefit from mixing both styles throughout the week.
Strength Training for Muscle and Bone
If you’re new to resistance training, two to three full-body sessions per week is enough to build noticeable strength. As you progress, three to four weekly sessions become necessary to keep improving, because muscles that are already adapted to training need a greater stimulus. Advanced lifters often train four to six days per week, splitting workouts by muscle group so each area gets sufficient work and recovery time.
The core principle behind strength gains is progressive overload: gradually increasing the weight, the number of repetitions, or the total volume of work you do over time. Without that progression, your body adapts and stops changing. You don’t need to add weight every session, but over the course of weeks and months, the demands should trend upward. Keeping a simple log of your exercises, weights, and reps makes it easy to see whether you’re progressing or plateauing.
One important finding for people worried about losing strength during busy periods: you can maintain muscle size and strength for up to 32 weeks with just one strength session per week and one set per exercise, as long as you keep the weight heavy. For older adults, maintaining muscle may require two sessions per week with two to three sets per exercise. The key takeaway is that intensity (how heavy you lift relative to your max) matters more than volume or frequency when the goal is simply holding onto what you’ve built.
Flexibility and Mobility Work
Stretching often gets skipped, but maintaining range of motion in your joints becomes increasingly important as you age and as strength training tightens certain muscle groups. The recommendation is to stretch all major muscle groups at least two to three times per week, spending a total of 60 seconds per stretch. If you can hold a stretch for 15 seconds, repeat it four times. If you can hold for 20 seconds, three repetitions will do.
Yoga and tai chi count toward this goal and add balance training as a bonus. Dynamic stretching (leg swings, arm circles, walking lunges) works well as a warm-up before exercise, while static holds are better suited to cool-down periods when muscles are already warm.
Protein and Recovery
Physically active people need more protein than sedentary ones. The International Society of Sports Nutrition recommends 1.4 to 2.0 grams of protein per kilogram of body weight per day for exercising individuals. For a 70-kilogram (154-pound) person, that’s roughly 98 to 140 grams daily. Spreading protein intake across meals throughout the day supports muscle recovery, immune function, and the growth of lean body mass.
Sleep is the other non-negotiable recovery factor. Sleep deprivation raises cortisol (a stress hormone that breaks down tissue) and increases the cortisol-to-testosterone ratio, creating a hormonal environment that works against muscle repair. While one night of poor sleep won’t erase your workout, chronically short sleep undermines the very adaptations you’re training for. Seven to nine hours remains the standard target for adults who exercise regularly.
Tracking Your Progress
Resting heart rate is one of the simplest indicators of cardiovascular fitness. The average resting heart rate is around 75 beats per minute. As aerobic fitness improves, that number drops. Resting rates consistently above 90 bpm are associated with higher health risk, while well-trained individuals often sit in the 50s or 60s. Checking your resting heart rate first thing in the morning, before getting out of bed, gives you the most consistent reading over time.
Heart rate variability, the variation in time between heartbeats, also increases with aerobic fitness. Higher variability generally reflects a healthier, more adaptable cardiovascular system. Many fitness watches and chest straps now track this automatically. Rather than comparing your numbers to someone else’s, watch for your own trends: a rising baseline over weeks and months signals that your training is working.
The Minimum to Maintain Fitness
Life gets busy, and knowing the minimum effective dose prevents all-or-nothing thinking. Research shows that endurance fitness can be maintained for up to 15 weeks by reducing your training to just two sessions per week, or by cutting your total volume by 33 to 66 percent (as little as 13 to 26 minutes per session). The catch: you have to keep the intensity the same. Easy jogs won’t preserve the fitness you built with hard runs.
The same principle applies to strength. One session per week at the same relative load can preserve your gains for months. Intensity is the single most important variable for maintenance, even when frequency and volume drop significantly. So during a hectic stretch at work or while traveling, a couple of short, hard workouts per week will hold the line far better than skipping exercise altogether.
Making It Stick Long Term
The biggest predictor of fitness over years isn’t the perfect program. It’s whether you keep showing up. Research on exercise habit formation points to two strategies that consistently help: planning and self-monitoring. Planning means deciding in advance exactly when and where you’ll exercise, not just intending to “work out more.” Linking a new exercise habit to something you already do daily (after morning coffee, during your lunch break) creates a reliable trigger that reduces the mental effort of getting started.
Self-monitoring can be as simple as marking a calendar or logging workouts in a phone app. Tracking creates a feedback loop: you see your consistency, notice patterns in what derails you, and build momentum from visible streaks. Motivation fluctuates, but habits run on autopilot. The goal is to repeat your exercise routine enough times, in the same context, that it stops requiring a decision and starts feeling like something you just do.