Precise time count for Nadi Shodana

"(The time taken by one), should he snap the fingers after circum-ambulation, neither too quickly nor too slowly, of the knee therewith, that is known as Matra (unit of measuring time). Filling in gradually the vital air through the Ida, for a duration of sixteen Matra-s, one should thereafter hold in the infilled air for duration of sixty-four Matra-s. He should, thereafter, expel (it) through the Pingala Nadi, for a duration of thirty-two Matra-s. Once again filling in (air) through the Pingala, (he should do) as before, with due control. He should gradually practise four times every day, up to eighty Kumbhaka-s, at daybreak, noon, sun-down and at midnight. "