In a typical triathlon, the average participant spends about a fifth of the total race duration swimming, half of the total race duration cycling, and about 30 percent of the total race duration running. You training should approximately match these distributions. Each week, you should do roughly equal numbers of swim, bike, and run workouts, but your bike workouts should be longer and your swims shorter. For example, if you work out six times, you will swim twice, bike twice, and run twice, but your longest bike ride might be one hour, whereas your swims last 30 minutes each and your runs, 40 minutes.

Begin with an amount of training that is appropriate to your present level of fitness and increase the workload incrementally throughout the time you have available before your race, always allowing yourself enough time for recovery. If you’re a typical out-of-shape adult who’s neither overweight, elderly, nor suffering from any debilitating medical conditions, you’ll need about 12 weeks to prepare for a sprint triathlon (0.25-mile swim, 15-mile bike, 3-mile run).

You may have heard triathletes or other endurance athletes talk about “intensity” and various workout types that target different intensity levels. Forget about this for now. While training for your first triathlon, keep the intensity level between 4 and 6 on a scale of 1 to 10 for all workouts.