Plants: haploid generation of a plant produces gametes (sperm and eggs) and is called the gametophyte; the diploid generation produces spores and is called the sporophyte/ diploid zygote.
1 You gain the most benefits and lessen the risks when you exercise in your target heart rate zone. 2  Usually this is when your exercise heart rate (pulse) is 60 to 80 percent of your maximum heart rate. 3  In some cases, your health care provider may decrease your target heart rate zone to begin with 50 percent.
So for a 20-year-old, the maximum heart rate would be 200 bpm, with a target heart-rate zone of 100 to 170 bpm. After exercising, a person's heart needs time to recover, or to return to its normal, resting heart rate. How long it takes for the heart to resume its resting rate is referred to as heart-rate recovery time.