Lougheed's family, in a prepared statement Tuesday, asked for privacy and promised updates as warranted.
"Peter Lougheed and his family are very thankful for all of your kindness and prayers at this time,” read the release.
Lougheed's Progressive Conservatives turfed the long-governing Social Credit in 1971 and are still in power more than 40 years later. Lougheed, who is 84, led the party until 1985.
The Calgary lawyer is credited with transforming the province into an economic powerhouse. Along the way he became famous for his fights with then-prime minister Pierre Trudeau over control of Alberta's oil wealth.
Many politicians, including current Premier Alison Redford, cite him as a profoundly influential role model.
"Our deepest thoughts and prayers are with the Lougheed family today," said Kim Misik, a spokeswoman for Redford.
"The former premier is someone that our current premier is very fond of and someone she looks to as a mentor."
Redford is in Asia on a trade mission and doesn't return to Canada until Monday.
She has known Lougheed dating back to her earliest years in politics. His public endorsement of her leadership in last spring's provincial election was seen as a important boost that helped the Tories return to power.
Many well-wishers, including opposition politicians, took to Twitter and Facebook on Tuesday to reach out to the former premier and his relatives.
"Our prayers are with premier Lougheed and his family," Alberta Liberal Leader Raj Sherman wrote on Twitter.
Despite being out of power for a generation, Lougheed has continued to wield considerable influence on public policy. He has spoken out in support of bilingualism, criticized the Kyoto accord to cut greenhouse gas emissions and cautioned against unbridled growth in the oilsands.
As premier he transformed Alberta from a largely agrarian region to a petro-powered player both nationally and internationally.
He helped patriate the Constitution, created a multibillion-dollar provincial trust fund and oversaw a broad expansion in funding for culture and the arts.
Most importantly, he diversified Alberta's economy by championing the oilsands, which today are responsible for delivering billions of dollars in annual revenue and are one of the key industrial drivers for the entire country.
This summer, Lougheed was named the best Canadian premier of the last 40 years by the Institute for Research on Public Policy.
In accepting the reward, Lougheed said he was gratified by the emergence of the Prairies, but told the audience: "Let's keep building."
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