President Obama recently savored the achievement, 8 million people signing up for health coverage on the federal exchange. He also touted something else: “ … real Medicare costs per person have stopped growing.” These have been the twin challenges of health care, expanding the number of Americans with health insurance, while holding down the increase in costs, addressing the inefficiencies, misguided incentives and inadequacies of the system.

What the president did not emphasize is that the modest increases in overall health spending the past seven years gave way to an acceleration last year. A February-to-February look at government data shows health spending increased 6.7 percent, or at the highest rate since 2007.

One reason appears plain enough. The economy has improved, many of us more likely to seek elective procedures from doctors and hospitals, insurers in better position to raise premiums, the government picking up a larger tab. So the recession and its aftermath no longer have such a dampening effect. Add to the equation a leading purpose of the Affordable Care Act, bringing health coverage to many without insurance, through the exchanges, plus the Medicaid expansion. The newly covered are more likely to see the doctor regularly and otherwise access the health system. So health spending increases.

The thought is, such preventive care eventually will work to help bend down the cost curve. Yet it hardly will be sufficient. The country must mobilize across many fronts to achieve the more difficult challenge of slowing health spending.

Jonathan Cohn of The New Republic recently helped put the task in perspective, highlighting the need to narrow the gap between the rate of economic growth and the rate of increased health costs. The difference the past 50 years has been 2.6 percentage points. More recently, it has declined to 1.6. The job ahead involves shaving off tenths from that point, even small progress yielding substantial savings over time.

The Affordable Care Act contains a range of initiatives and experiments aimed at getting there. Some even have begun to show results, such as incentives for reduced readmission rates at hospitals. One yet to take effect is the “Cadillac tax,” a levy to discourage the most generous coverage. This step reflects the broader trend of requiring individuals to assume a greater share of the cost, to be more discriminating not in emergencies but in choosing elective procedures.

Many analysts argue that the country will help itself considerably by moving away from the fee-for-service structure. That makes sense. It also will prove hard, reducing health spending also means reducing the income of providers. Yet the savings are essential. Which explains the rattled nerves as health spending climbed the past year. If health costs are not contained, the country will lack the resources necessary for such crucial priorities as education, public works, research and development and aiding the disadvantaged.