During sleep deprivation, people with chronic insomnia don't show as much increase in parasympathetic activity at night compared to healthy people. This finding is from the abstract summary - full study details were not available

Both people with chronic insomnia and healthy sleepers experience increased parasympathetic activity at night during sleep deprivation. This finding is from the abstract summary - full study details were not available

Healthy sleepers show stronger sympathetic nervous system activity during sleep deprivation compared to those with chronic insomnia. This finding is from the abstract summary - full study details were not available