With lack of exercise, the heart beats less efficiently and the stroke volume decreases. By this is meant that less blood is pumped out of the heart with the average heart beat. With stress, the heart rate increases, but the stroke volume may actually decrease. Not efficient. Persons in good physical condition have a lower resting heart rate and a larger stroke volume. More efficient.
Cigarette smoke has similar effects on respiratory system no matter how it is ingested. Tobacco users inhale mainstream smoke through the cigarette and secondhand smoke in the air. Breathing any amount of secondhand smoke raises the risk for many health problems. Toxic particles that cling the smokers` clothes and hair can contaminate indoor environment as dust.