Charak Samhita
दिवा प्रबुध्यतेऽर्केण हृदयं पुण्डरीकवत्। तस्मिन्विबुद्धे स्रोतांसि स्फुटत्वं यान्ति सर्वशः॥२३८॥
since in day time all the srotas (channels) are dilated and heart is active similar to the lotus which blossoms with sunrise.
english translation
divA prabudhyate'rkeNa hRdayaM puNDarIkavat। tasminvibuddhe srotAMsi sphuTatvaM yAnti sarvazaH॥238॥
hk transliteration by Sanscript