Which lifestyle factor significantly increases the risk of post-operative complications?

Smoking is significantly associated with an increased risk of post-operative complications due to its detrimental effects on various physiological processes. Nicotine and other harmful substances in tobacco smoke can impair wound healing, increase the likelihood of respiratory complications, and negatively affect blood flow and oxygen delivery to tissues. Smokers are at a higher risk for developing infections and can experience delays in recovery and increased mortality rates post-surgery. Additionally, smoking can lead to vasoconstriction and reduced oxygenation, which are critical for healing processes following surgical procedures.

While obesity also poses significant risks, including wound infections and complications related to anesthesia, smoking remains one of the most critical factors directly linked to adverse surgical outcomes. High caffeine intake and excessive exercise generally do not carry the same level of evidence of increased post-operative risk like smoking does.