WASHINGTON — Cardiologists not associated with the White House said Wednesday that President Trump’s physical exam revealed serious heart concerns, including very high levels of so-called bad cholesterol, which raises the risk that Mr. Trump could have a heart attack while in office.

Dr. Ronny L. Jackson, a rear admiral and the White House physician, said Tuesday in his report on the president’s medical condition that Mr. Trump was in “excellent” cardiac health despite having an LDL cholesterol level of 143, well above the desired level of 100 or less.

Dr. David Maron, the director of preventive cardiology at Stanford University’s medical school, said Wednesday that it was alarming that the president’s LDL levels remain above 140 even though he is taking 10 milligrams of Crestor, a powerful drug that is used to lower cholesterol levels to well below 100.

Dr. Maron said he would “definitely” be worried about Mr. Trump’s risk for having a heart attack if the president were one of his patients. Asked if Mr. Trump is in perfect health, Dr. Maron offered a blunt reply: “God, no.”

Other cardiologists also disputed Dr. Jackson’s rosy assessment of the president’s heart health. Several said Mr. Trump’s goal should be to get his LDL below 100, or even under 70. He has a real risk of having a heart attack or stroke, especially considering his weight and lack of exercise, they said.

Dr. Eric Topol, a cardiologist at the Scripps Research Institute, said that it is impossible to ignore the dangers of the president’s elevated cholesterol levels when providing an overall assessment of Mr. Trump’s health.

“That’s a really high LDL,” Dr. Topol said. “We’re talking about a 70-plus-year-old man who is obese and doesn’t exercise. Just looking at the lab value, you would raise a big red flag.”

He added: “I would never use the words ‘excellent health.’ How you could take these indices and say excellent health? That is completely contradicted.”

During an appearance on Tuesday in the White House briefing room, Dr. Jackson said he would be prescribing a higher dose of Crestor, the brand name for rosuvastatin, to help lower the president’s LDL levels. All of the cardiologists said that would be essential in trying to control Mr. Trump’s risk of a heart attack, though several said they wondered whether Mr. Trump was regularly taking his medicine as prescribed.

Dr. Daniel Rader, the director of the lipid clinic at the University of Pennsylvania’s medical school, said that taking a daily dose of 10 milligrams of Crestor should reduce LDL levels by at least 30 percent, which means that Trump’s LDL started out over 200, a dangerous level.

“One obvious question is, how long has he been on a statin?” Dr. Rader said. “What was his LDL before he started taking it?”

He noted that a man who recently started taking a statin and who had an LDL over 200 for most of his life is at much higher risk than someone whose LDL was normal until recently and who then started taking a statin.

Dr. Jackson said he is also pressing Mr. Trump — who at 6-foot-3 and 239 pounds is just below the official label of obese — to eat better and abandon his largely sedentary life for one that includes exercise.

But on the positive side, Dr. Jackson also said Mr. Trump had no history of smoking or drinking and did not have diabetes. An exercise stress test using a treadmill showed “above average” capacity for his age. An ultrasound of the heart was normal, he said.

“His cardiac health is excellent,” Dr. Jackson said. “He doesn’t smoke, he doesn’t have diabetes — a lot of the traditional risk factors he doesn’t have. And so I think those things, in combination with the excellent cardiac results that we got from the exercise stress test, I think, are very reassuring.”

Outside doctors — who have not directly examined Mr. Trump — questioned that conclusion, saying that the combination of Mr. Trump’s weight and the cardiac test results raised more concerns than Dr. Jackson’s comments would reflect.

That helped spark a flurry of activity on Twitter, where people debated whether the president officially had heart disease, based on the lab results released by Dr. Jackson and his comments to reporters.

Dr. Topol and the other cardiologists contacted Wednesday disagreed with Dr. Gupta about the calcium test, which measures the amount of plaque containing calcium in a person’s blood. Higher numbers indicate the development of coronary artery disease, which could lead to dangerous blockages in the heart.

But Dr. Topol said he would not be concerned unless a patient of Mr. Trump’s age came to him with calcium levels of 700 or more.

“That tells you there’s some calcium,” he said. “It doesn’t tell you whether that’s inside or outside the arteries. That doesn’t tell me the risk.”

Dr. Rader and Dr. Maron said Mr. Trump’s calcium score does not mean much. If people take statins their calcium scores go up because statins help plaques heal and leave behind calcium-containing scar tissue.

“I have seen this so many times. I tell people who have been on statins not to have it redone,” Dr. Rader said.

The cardiologists said the president’s weight and diet were a serious problem that probably contributed to his high LDL level and increased his risk for heart problems. Dr. Topol dismissed as irrelevant the debate about whether the president technically met the definition of obese.

“Here the issue is, does he have abdominal obesity?” Dr. Topol said. “I don’t care what his height is. All you have to do is look at his abdomen. Abdominal obesity, that’s the machinery for inflammation for the heart.”

Sarah Huckabee Sanders, the White House press secretary, stood behind Dr. Jackson’s assessment of the president’s health, noting on Wednesday that he has been a White House physician for 12 years, treating Presidents George W. Bush and Barack Obama in addition to Mr. Trump.

“He is the only doctor that has weighed in on this matter that has actually examined the president,” Ms. Sanders said. She called Dr. Jackson “the only credible source when it comes to diagnosing any health concerns.”

We support what he said yesterday 100 percent — that he is in excellent health,” she said.

Several former members of Mr. Obama’s White House staff echoed that praise of Dr. Jackson.

David Axelrod, who served as one of Mr. Obama’s top advisers in the White House, said Tuesday on Twitter: “I knew Dr. Ronny Jackson in the White House. In my experience, he was very good guy and straight shooter.”

Even so, the cardiologists said Dr. Jackson understated the president’s risk of having heart trouble. Dr. Maron calculated the president’s risk of having a heart attack or stroke in the next 10 years, based on the high LDL levels and normal blood pressure. The result placed him in the top 25 percent of the population.