It's a bit of a myth that you need to "hit the gym" to gain strength and fitness, however. For example, I've lost several stone and gained considerably in endurance just by spending 10 minutes a day doing press-ups and planking (5 batches of 20; takes literally no time at all), and by walking for 40 minutes every day (two quick 20 minute walks). Hardly a gruelling, time-consuming routine, and yet I'm fitter, healthier, stronger, and more defined. How much fitter then, for example, could someone who is trekking, travelling, and enduring hardships *every day while adventuring* become? I can tell you, unless they've some way of avoiding even the most basic of exercise involved in an adventuring life (or there is a medical reason for being frail), they will reach at least average fitness levels in pretty short order, even if they were lower to begin with.