It’s been about four months since President Donald Trump threatened sanctions against countries supplying much-needed oil to Cuba.The move has added pressure to an economy already struggling with shortages, inflation, and rolling blackouts — all while Cuba continues to navigate the effects of the longstanding U.S. embargo.Marta Núñez-Sarmiento is a sociologist and retired professor at the University of Havana, whose work has explored gender, migration, and economic change in Cuba. Her WhatsApp messages to me often ended with updates on the power situation.She went about 17 hours without electricity before our first phone call. Roughly an hour later, another blackout — after about two hours of “light.”Politico reported in early May that a carton of 30 eggs on the island cost about $125. Cubans have access to government-issued ration books, but supplies remain extremely limited. Some residents have turned to charcoal fires amid a shortage of cooking gas.But even in a crisis, life continues. Núñez-Sarmiento said the school near her neighborhood in Havana is still running, although she said the first thing kids ask on their way home is whether or not there is power. “The general mood is stress,” she said. “We're in a hole, we're in a deep hole, and there's no light at the end.”Conversations in her neighborhood normally center on the obvious: blackouts, price of food and medicine, and frustrations with the government. Then, she said, they talk about the latest soap opera drama. Núñez-Sarmiento, who turns 80 in July, has lived through nearly every major chapter of Cuba’s modern economy — from the rise of Fidel Castro to Cuba’s current economic crisis.She describes how the Cuban economy has changed over the decades, from the Cuban Revolution to the fall of the Soviet Union and the island’s recent migration wave.To hear Núñez-Sarmiento describe how the Cuban economy has changed over the decades, click the audio player above.