This story has been updated with the news that Alexei Navalny ended his hunger strike.

Hunger strikes take a tremendous toll. In just a few days, physical and mental effects begin to set in. Ultimately, they can lead to death.

For prisoners who undertake them — such as Russian opposition leader Alexei Navalny, who said Friday he would end his hunger strike after 24 days and is now under treatment at a high-security prison east of Moscow — the painful toll is part of the point: The weakening and wasting of the body shows strength of determination.

Hunger strikes have a long history in Russia. Some of the first modern hunger strikers were 19th-century Russian prisoners who refused food to protest the conditions of their confinement in the czar’s lockups. Word of their deeds spread across the world, influencing many prisoners and dissidents.

“The prison hunger strike developed as an international form of protest from a few different sources, of which Russian revolutionaries were the most influential,” said Kevin Grant, a historian at Hamilton College who has tracked the evolution of the practice.

In the 20th century, imprisoned Soviet dissidents drew global attention to their plights with high-profile voluntary deprivation of food. In the 1980s, the death of prisoner Anatoly Marchenko, two weeks after he ended a hunger strike, may have prompted Mikhail Gorbachev to release other political prisoners.

Navalny, 44, Russia’s best-known opposition leader and the survivor of a nerve agent attack last year that almost killed him, has said he has been on a hunger strike since March 31 because prison officials will not let his doctors visit him. He is in prison for a parole violations, but supporters and experts say the charges are political.

Although his strike was focused on a narrow demand, international observers see it more broadly, as an act of resistance against the government of President Vladimir Putin, who has led Russia for more than two decades.

Putin allies were widely suspected of poisoning Navalny.

For Navalny’s hunger strike, the stakes were high. His personal physician, Yaroslav Ashikhmin, said last week that blood tests show the activist could die “at any moment.” Foreign officials from the United States and Europe warned that there will be consequences if Navalny were allowed to die during the hunger strike.

“Aleksei Navalny is being murdered in front of the world by Vladimir Putin for the crime of exposing Putin’s vast corruption,” Sen. Bernie Sanders (I-Vt.) wrote on Twitter.

The act of refusing food for political reasons has a long history. But prison hunger strikes became an established practice in the 19th century, before spreading widely in the 20th.

The tactic was used by suffragists in Britain, independence movements in Ireland and India, anti-apartheid leaders in South Africa and Palestinians in Israeli prisons. Hunger strikes have occurred at the U.S. military prison at Guantánamo Bay, Cuba, prompting controversy about force-feeding by U.S. authorities.

One of the most influential early hunger strikes began in 1878, in the Peter and Paul Fortress in St. Petersburg, where a group of imprisoned Russian revolutionaries refused food in a bid to improve their status.

Their captor, Nikolay Mezentsov, was unmoved, reportedly saying: “Let them die; I have already ordered coffins for them all.” But the strike found support outside prison walls and a sympathizer stabbed Mezentsov to death before escaping to London.

Suffragists in the British capital soon began referring to hunger strikes as the “Russian method,” according to Grant’s research, and adopted it themselves. The tactic spread to Irish republicans and Indian nationalists.

Another Russian hunger strike drew international attention in 1889, when a group of women serving at a notorious prison labor camp in Transbaikal, Siberia, refused food to protest their brutal treatment. Some of the women, as well as male supporters, later killed themselves with poison.

That incident, which international media outlets referred to as the “Kara tragedy,” prompted significant reforms, including the closure of the labor camp and the prohibition of corporal punishment for imprisoned women.

George Kennan, an American writer and relative of a well-known U.S. diplomat with the same name, also recounted the details for an American audience — translating the Russian word used, golodovka, as “hunger strike,” a novel concept at the time.

The practice continued after the end of Tsarist Russia and into the Soviet Union, where dissidents used hunger strikes to draw attention to their plights in the Gulag system of forced labor camps.

Jacques Rossi, a Polish-French writer who later drew attention to the Gulags through firsthand accounts, recounted hunger strikes in the late 1940s and 1950s. Other well known activists such as Andrei Sakharov conducted their own hunger strikes in the 1970s and 80s.

Although the fasters sometimes won concessions, it was often at a brutal cost. Rossi recounted a policy of force-feeding orally and rectally. Sakharov, a nuclear physicist and human rights activist, also told of brutal force-feeding.

Doctors “kept changing the method of force-feeding … to maximize my distress to make me give up,” Sakharov wrote of a hunger strike in 1984 in a letter to Western newspapers.

Marchenko, a dissident who had undertaken many hunger strikes during the two decades he spent in Soviet prisons, died in 1986 following a four-month fast. His death caused an international outcry, putting pressure upon on the reformist Soviet leader Gorbachev to change the Soviet penal system.

Long after the Soviet Union collapsed, some aspects of the penal system remained. Many of Russia’s prisons are isolated colonies, with inmates housed in dorms and forced to work. Accounts of extreme punishment by guards, even torture, continue.

High-profile inmates such as Putin critic and oligarch Mikhail Khodorkovsky and members of the protest punk band Pussy Riot have staged hunger strikes. Ukrainian filmmaker Oleg Sentsov undertook a 145-day hunger strike in 2018 to protest his 20-year sentence on terrorism charges, coming perilously close to death.

“Without a doubt, this is an instrument of protest that is trending upward in Russia,” Natalia Taubina, director of the human rights organization Public Verdict Foundation, told the Moscow Times during Sentsov’s strike, adding that prisoners “had no other protest tools.”

At the prison to which Navalny has been transferred, the glumly named Penal Colony No. 3, there is a history of protest. In 2005, hundreds of prisoners slashed their necks and wrists in protest after claims of beatings by prison guards. The prison’s senior staff members were later fired.

No hunger striker has died in a Russian prison since Marchenko. Russian authorities threatened to force-feed Sentsov, according to accounts from his attorney, but he was later freed in a prisoner swap. Navalny said Friday that he had ended his hunger strike on the advice of his doctors who warned he could soon die.

Grant cautioned that there may be a gulf between how a hunger strike was interpreted domestically and the response internationally. “If prison hunger strikes have anything in common, it is the prisoner’s decision to challenge the state’s authority as a protector and a provider for society,” he said.

Grant said that they do this by serving as the “sacrificial embodiment of the state’s violence and injustice, thus challenging the state’s rule of law as immoral.”

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