Immediate effects carbon monoxide levels in the lungs increase so that more effort must be made to achieve the same physical results as a non-smoker initial stimulation, then reduction in brain and nervous system activity enhanced alertness and concentration mild euphoria heart rate and blood pressure increase decreased blood flow to body extremities like the fingers and toes relaxing skeletal muscles and increasing tension in other muscles reduced lung capacity due to increased resistance in the airways dizziness, nausea, watery eyes and acid in the stomach decreased appetite, taste and smell.