Yes, exercise means more work to your muscles, cells, organs etc.,
More work means more glucose and more oxygen is required to be supplied
to these cells, muscles.
This more glucose and oxygen is supplied through blood,
and the blood is supplied by the Heart, which sucks dull blood and pumps
good blood throughout the body.
so more work for the heart and lungs. If your heart is at rest then less work
your heart can manage it easily. But work out demands but your heart is
getting tired sooner while doing extra work. The Heart is suffering the pain.
If you give extra work to the Heart then you should give extra nourishment to
the Heart, Otherwise do less exercise.!
If you keep doing the same then your Heart will tire out and the efficiency of the
Heart will reduce. bcz your muscles may be strong to lift the Heavy weight
but not your Heart.!
Caution now and prevent any further damage to your heart, "Prevention is better than Cure".