In much of the world, a new year means a fresh start – a time for resolutions, gym memberships, and promises to be more productive. In Russia, it means two weeks of heavy drinking.

The country is just starting to emerge from its latest binge, which launched on New Year's Eve and ended, unofficially, with a second new year's celebration on Sunday. Yet medical officials warn that full recovery may be a long time coming.

"Long holidays are, in any event, bad," Yevgeny Bryun, Russia's top medical drug official, said on Monday. "Long-term abuse of any alcohol is always bad – it has chronic toxic impacts, the effects of which can last a month."

He added: "Alcohol is only fully processed after three weeks."

Russia only opened for business on 9 January, the first day back to work after its extended new year's holiday, during which life all but comes to a standstill: stock markets are shut and no newspapers are printed. Many extend the festivities until 13 January, when Russia celebrates the new year according to the old Julian calendar.

Economists estimate that Russia's GDP misses out on 1 trillion roubles (£20bn) as a result of the extended holiday, according to RIA-Novosti, a state-run news agency.

But it's a time Russians hold dear. Some flee the country for warmer climes, leaving Moscow something of a ghost town. Many more simply "dive into a zapoi", a ubiquitous Russian term for binge-drinking.

One expert estimated that if all the bottles of alcohol that Russians drank over the holiday were lined up along the equator, they would wrap around the world 17 times. Vadim Dobroz, head of Russia's Research Centre on the Federal and Regional Alcohol Market, added that the average Russian spent 12,000 roubles (£247) on alcohol during the period.

Norma, a medical research network, went further, estimating that Russians, with a total population of 142 million, drank more than 1.5bn litres of alcohol over the holiday, including 100m bottles of beer, 100m bottles of champagne and 250m bottles of vodka, its national drink. Add to that 80m bottles of wine, 10m bottles of cognac and 1.5m bottles of other drinks such as rum, gin, tequila and whisky, and the total sum is dizzying.

Russian newspapers and websites are now filled with advice to the millions of Russians attempting to re-enter sobriety.

"The holidays are just holidays for regular people, but for doctors, especially drug doctors, they are hard-working days," begins an article on MedPortal, a Russian health network. "The real fun begins three to four days after the holiday ends. Citizens, who have abused alcohol for at least 10 days (and some started in mid-December even), suddenly remember that they need to go to work."