Table 2.

Correlation between meditation experience/expertise and alertness

Study	Expertise	Alertness/sleepiness	r value (Pearson)
Self-report measures
Ong et al.132	KIMS score	Diary-rated daytime sleepiness	–0.65*a (post-treatment) –0.71**a (6 months) –0.54*a (12 months)
		Diary-rated daytime tiredness	–0.66**a (post-treatment) –0.62**a (6 months)
Cahn and Polich160	Years of daily practice	Drowsiness during control condition	–0.60*
Brittonet al.175	Frequency of practice in mindfulness-based sleep treatment (5–10 min/day, 2–3 days/week)	Diary sleep duration	+0.56*
	Minutes of home practice during MBCT	Total (diary) sleep time	–0.80**
Neuroimaging measures (EEG, fMRI)
Brittonet al.164	Minutes of home practice during MBCT	Increase in stage-1 minutes during sleep	0.80**
	Minutes of home practice during MBCT	Increase PSG awakenings and arousals during sleep	0.57*
	Frequency of practice (times per week)	Decrease in percent of slow-wave sleep (stages 3/4)	–0.62*
Ferrarelli et al.165	Lifetime daily practice hours (non-retreat)	Increased occipital-parietal gamma during NREM sleep	0.48**a
Luderset al.95	Lifetime hours of meditation practice	Increased gyrification in R anterior insula	NR
Holzel et al.82	Lifetime hours of Vipassana meditation	Increased volume of R anterior insula	0.36#
Hasenkampet al.65	Lifetime hours of meditation practice	Decreased activity in DMN	–0.74***
Baron et al.78	Lifetime hours of meditation practice (<10 years vs.>10 years)	Activation of DLPFC and ACC during mindfulness meditation	NR
Behavioral Measures
Jhaet al.49	Lifetime meditation experience	Magnitude of the alerting score post-retreat (negative value indicated better performance)	–0.52*
Valentine and Sweet40	Meditation experience	Performance on tonic alerting task	NR

^aSpearman’s rho

KIMS= Kentucky Inventory of Mindfulness Scale; NR= not reported.

^*P< 0.05

^**P< 0.01

^***P< 0.005