Sympathetic activation is required for attention. Separate studies have shown that meditation ( a) improves attention and ( b) reduces sympathetic activity. The present study assessed attention with the P300 and sympathetic activity with heart rate variability (HRV). Forty-seven male subjects (group mean age ± SD, 21.6 ± 3.4 years) were assessed in 4 mental states: ( a) random thinking, ( b)...