What does running do for your body?
Make movement part of your week. We explain the evidence that motivates us, then show you a first session you can actually picture.
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General information, not individual medical advice. For questions about symptoms or readiness to run, speak with a clinician who knows your health history.
Give aerobic fitness a place in your week
We build First Gear because starting running deserves a clear first step. The research on aerobic fitness gives us a reason to care about regular movement. You can start with a walk; you do not need an athlete's goals or a target number.
Aerobic fitness describes how well your body supplies and uses oxygen during activity. VO2 max is one measure of that capacity. [3]
In a study of 122,007 adults referred for treadmill testing, higher fitness was associated with lower mortality over a median follow-up of 8.4 years. This was an observational study of patients, not a trial assigning beginners to running. It cannot show how much longer a particular person will live. [2]
A separate meta-analysis also found lower mortality and cardiovascular-event risk among people with higher fitness. [3] We take that evidence as a reason to make room for activity. These studies do not establish a health outcome from using First Gear.
Does running preserve muscle as you age?
A study of 40 masters athletes, ages 40 to 81, found no significant decline in mid-thigh muscle area with age. Participants trained four to five times a week. Researchers compared different people at one point in time, rather than following the same muscles over forty years. [1]
We find that encouraging, with a clear limit: the study does not show that running alone stops muscle loss, or that a beginner will develop the same muscle as a longtime athlete. Let it broaden what you imagine for an active later life without turning someone else's body into your target.
Give the rest of your routine attention, too. NIH guidance includes resistance and balance work alongside weight-bearing activities such as walking and running. [6] Our run/walk coaching fits into that wider picture; it does not need to be your whole exercise plan.
Start from the week you have now
A 2022 review of masters endurance athletes found that changes in training volume were related to changes in aerobic fitness over time. Age, health, and the reasons someone changes their training still matter. [4]
Our approach is to give you something small to practice now. Choose an amount of activity that fits your current circumstances, then give yourself room to adjust. In First Gear, a session begins with walking and has a twenty-minute target. You choose how much jogging to take on when our coach cues it.
Let us turn the heart-rate number into a next step
A readout on your wrist can leave you wondering what to do with it. In standard range coaching, First Gear follows your Apple Watch heart-rate readings and recent trend, then cues a jog or a walking break. Choose Lana or Cal as your coach, hear the next cue, and keep your own pace.
Heart rate is one signal. It cannot tell us whether your joints are ready for impact or explain why you feel unwell. A comfortable conversation is another way to check effort; the CDC uses the talk test as a general guide to activity intensity. [5] You can always slow down, keep walking, or stop.
Set aside twenty minutes, choose a familiar path, and try your first session free with no subscription. We start you with a walk. There is no pace to hit and no requirement to run the whole session.
Turn the reading into your first session.
Put on your Apple Watch and let us coach the next twenty minutes. First Gear starts with a walk and cues each jog and walking break. Your first session is free, with no subscription.
Common questions
Is it too late to start running in your 50s or 60s?
Your age alone does not choose your next step. We encourage you to start from the activity you can manage now, which may be walking, and get advice about health concerns or existing pain. Research on experienced older athletes gives us encouraging context, not a forecast for a new runner.
Do I need to know my VO2 max before I start?
No. We do not ask you to earn a VO2 max score before your first walk. It is a fitness measure used in research and training. First Gear starts with walking and uses heart-rate readings to guide jog/walk cues in standard range coaching.
What is a manageable first step?
Choose a familiar path and start with a walk, leaving room to turn back early. If you want coaching for the changes between walking and jogging, try First Gear on Apple Watch. The first session has a twenty-minute target and is free, with no subscription. You can walk all of it.
References
- Wroblewski AP, Amati F, Smiley MA, Goodpaster B, Wright V. Chronic Exercise Preserves Lean Muscle Mass in Masters Athletes. The Physician and Sportsmedicine 39(3):172-178, 2011.
- Mandsager K, Harb S, Cremer P, Phelan D, Nissen SE, Jaber W. Association of Cardiorespiratory Fitness With Long-term Mortality Among Adults Undergoing Exercise Treadmill Testing. JAMA Network Open 1(6):e183605, 2018.
- Kodama S, Saito K, Tanaka S, et al. Cardiorespiratory Fitness as a Quantitative Predictor of All-Cause Mortality and Cardiovascular Events in Healthy Men and Women: A Meta-analysis. JAMA 301(19):2024-2035, 2009.
- Burtscher J, Strasser B, Burtscher M, Millet GP. The Impact of Training on the Loss of Cardiorespiratory Fitness in Aging Masters Endurance Athletes. International Journal of Environmental Research and Public Health 19(17):11050, 2022.
- How to Measure Physical Activity Intensity. Centers for Disease Control and Prevention, 2025. Accessed 2026-09-11.
- Exercise for Your Bone Health. National Institute of Arthritis and Musculoskeletal and Skin Diseases, 2023. Accessed 2026-09-11.