"Ramdev was admitted to the ICU immediately after he was brought to the hospital where doctors have examined him," Medical Superintendent of Himalayan Hospital, Jolly Grant, Dr S L Jethani said.
Doctors said Ramdev is being administered glucose.
Jethani had earlier refused to go into details about the condition of the 46-year yoga guru, saying that a statement on his health would be given only after thorough examination.
Ramdev was shifted to the Dehra Dun hospital, 25 km from Patanjali Yogpeeth in Haridwar, where he had been fasting on issues of curbing corruption and bringing back black money stashed away in foreign banks.
Uttarakhand Health Director General, Dr Asha Mathur said Ramdev was hospitalised as his health was deteriorating.
She said two medical teams have been constituted to keep a constant watch on his condition and medical bulletins would be issued regularly.
Citing his health parameters, Mathur said Ramdev's "blood pressure is 104/70 while pulse rate is 56, which normally should have been between 70-75. An infection has also been found in his urine."