Select from options: Continue writing the next sentence.

How to raise your heartbeat
Change how you sit.
Instead of just sitting in a normal chair, try sitting on an exercise ball instead. Sitting on an unstable surface engages and strengthens your core muscles while sitting in a normal chair does not.

Available options:
[1]. Different people put different positions on the ball. Try to try different positions to increase your comfort.;
[2]. You can even forgo sitting, and stand as much as possible during the day. Even these small changes can affect your heart.;
[3]. Exercise balls may help you urinate, push yourself, or widen your abdominal opening. Replace an exercise ball with a cloth or a ball kept in a safe place.;
[4]. On a standing stability ball, push yourself up, keeping your leg and arm resting on the ball. Try some variation of the seated adjustments.;
Answer:
[2].