Short answer: yes, but with some care — especially in the first couple of weeks. Here's what actually matters.
Swimming
Chlorine and salt water can both dull and dry out treated hair. Rinse your hair with fresh water before swimming to reduce absorption, and always shampoo and condition afterward. Wait at least two weeks post-treatment before regular pool sessions if you can.
Sweating and workouts
Light workouts are fine after the initial 72-hour setting window, but heavy sweating combined with humidity can affect how smooth hair looks day to day — it won't undo the treatment, but you may notice more frizz on high-sweat days.
The bottom line
None of this means you have to put your routine on hold. It just means being a little more deliberate — rinse before, wash after, and give the treatment those first couple of weeks to fully settle in.
— Rym