Only the body is in the now
In spacetime, now is time zero, relative to itself. Now is now everywhere at time zero.Any movement, tactile or conceptual, changes the time coordinate, taking the mind away from the body to the past or the future.
Reality is the present moment thus has no time associated with it. Awakening to this reality can only happen at the present moment. Reality can not be at any time other than zero, i. e. It can not be in the past or the future.
Emotions like fear or anger are body's reaction to thoughts, often from the past or about the future. They can not happen at any other time only at time zero or now.
So when mind goes to the future or the past, it brings all of the resulting emotions to the present. The clear antidote for suffering from such emotions is not to stop thinking, an impossible task, but to bring the mind back to the present exactly where the body is.
Mindfulness meditation or yoga alleviates suffering by bringing the mind back to reality which exists only in the present moment.
By going back and forth from the past to the future you are subjecting the body to unnecessary stresses, highs and lows. This is suffering and cause of most illnesses of the body.