Which of the following is NOT a health effect of smoking?

In the context of health effects associated with smoking, increased energy levels is not a recognized consequence. Smoking is widely known to have numerous harmful effects on the body, including a variety of respiratory diseases and cancers.

Lung cancer, emphysema, and chronic bronchitis are all serious conditions directly linked to smoking. Lung cancer is one of the most lethal cancers and is heavily associated with tobacco use. Emphysema is a progressive disease that damages the air sacs in the lungs, making it difficult to breathe, and is a major component of chronic obstructive pulmonary disease (COPD). Chronic bronchitis involves long-term inflammation of the airways, leading to a persistent cough and mucus production, and is also closely related to smoking.

Thus, the assertion that smoking can lead to increased energy levels contradicts the overwhelming evidence of its detrimental effects on respiratory health and overall physical condition. Smoking typically leads to a reduction in stamina and fitness levels, resulting in fatigue and decreased energy rather than an increase.