Table 2.

Pearson correlation coefficients between muscle FNDC5 and serum irisin, with lung FNDC5 continuous exercise training

	Groups	Muscle FNDC5	Serum irisin
Lung FNDC5	Control	r = 0.57, p = 0.314	r =  − 0.33, p = 0.583
	SeNPs	r =  − 0.49, p = 0.393	r = 0.12, p = 0.846
	AIT	r = 0.01, p = 0.983	r =  − 0.25, p = 0.674
	AIT + SeNPs	r = 0.85, p = 0.066	r = 0.93, p = 0.021*
	CSE	r = 0.43, p = 0.463	r = 0.04, p = 0.941
	CSE + AIT	r =  − 0.38, p = 0.519	r = 0.37, p = 0.539
	CSE + SeNPs + AIT	r = 0.92, p = 0.025*	r = 0.34, p = 0.571

r = Pearson correlation coefficient; p = p value; correlation is significant for p < 0.05 *, SeNPs nano-selenium; AIT aerobic interval training; CSE cigarette smoke extract