When you are weight lifting/weight training, or doing any high intensity workout you need timed rest intervals between your work sets. The length of the rest break is important, too short and you will not recover enough to do the next set, too long and you could reduce the training benefit, cool down or waste time.
Gym rest timer makes timing your rest breaks easy. It includes big buttons (for shaky hands) for all the main rest break periods. You could just use your phone clock, a stopwatch, a countdown timer or any other type of timer (even old school manual), but Gym Rest Timer makes it simple, a single click, in fact. No typing in the number of seconds, or scrolling to get your rest length. Finish your set, click a button, rest, when it beeps do your next set.
Gym Rest Timer is mainly aimed at people following a resistance training programme. To get the maximum benefit from lifting weights (or cables/bands/bodyweight/other resistance) you need to rest the appropriate time between sets. For endurance work, rest breaks tend to be shorter, for strength training a bit longer.
For high intensity interval training (HIIT or HIT) you could just about use this version of Gym Rest Timer but its more use for weightlifting. A repeating interval timer is in the pipeline for a future release.
During warm up sets, just take the time needed to load the bar, or adjust the machine
During work sets: if the set was easy take 30 seconds, if ok take 60, if tough but bearable take 90 seconds. If you only just made the last rep take 2 or 3 minutes, if you failed, or badly lost form on the last rep, take the full 5 minutes.
What to do in your rest? some people just sit, some keep moving, some gently stretch the worked muscles.
If you are new to weight training make sure someone competent checks your lifting form, lifting big weights badly can cause proper injuries.
Have fun, let us know any comments or suggestions.