Nicotine releases dopamine, which lowers stress and brings short-term relaxation. However, as soon as dopamine levels drop, stress and fatigue come rushing back, explained Dr Vikas Mittal, Pulmonologist. "It may feel like smoking is helping you stay awake, but [it's]...due to adrenaline," he added. This surge is followed by increase in pulse rate, which worsens inflammation in body and lungs.