, Mr Russell said that evidence was emerging from the first year of National 4 and 5 that pupils taking eight subjects thought this had been "too pressured".
"It [the number of subjects] will never be standardised - it shouldn't be - but I think we will see a coalescence around six," Mr Russell said.
Many parents have expressed fears that fewer subjects will result in a narrowing of their children's education. Teachers have also suggested that sciences and languages will experience reduced interest.
Mr Russell, however, said he had seen no evidence of this. He added that a national focus on sciences and the 1+2 languages policy, which aims to get primary pupils studying two foreign languages, would counteract any pressure on those subjects.
Meanwhile, the education secretary revealed that he had discussed with headteachers the idea that some pupils bypass National 5 altogether, instead doing Highers over two years. "I think a lot of people would expect National 4 and 5 to diminish in importance over the years.because I think there will be more of a trajectory towards Higher," he said.
Fears that parents would be sceptical about the exam-free National 4s and push children to do National 5s before they were ready had not been borne out, Mr Russell said. Worries that schools would add considerably to their workload by presenting pupils for both levels en masse as a safety net had also not come to pass.
"I think we should be very positive about the experience we've had with this first diet," the education secretary said. "It has been exceptionally positive."
Mr Russell's comments come after a difficult year for teachers following the introduction of significant exam reforms. But the education secretary predicted a smoother ride with the new Highers, which will run concurrently with the old qualifications this year.
"The difference between the two is not as great as it was, for example, between Standard grade and National 5," Mr Russell said, adding that both versions would have equal value and nothing would differentiate them on pupils' certificates.
Meanwhile, he said he had been encouraged by a system of teaching he saw recently in New Zealand - a school designed architecturally to optimise different-sized groups of pupils and teachers in different kinds of spaces, depending on what worked for each lesson.
"The headteacher didn't think it was an organisational nightmare - he thought it was a pleasure, an inspiration," Mr Russell said. "I think we have got some learning to do about that."
He also said that the baccalaureate, which attracted only 176 candidates last year, would be a greater priority for him in 2014-15, and promised that supply teachers would benefit from the Professional Update scheme to reaccredit staff, saying "it would be quite wrong to leave them out in the cold".
Mr Russell was adamant that further education reform had been "necessary and has worked well". The recent suggestion by Scottish Labour, using Colleges Scotland data, that 10 million learning hours had been lost in three years was "misinformation", he said.
Recent evidence that courses for additional support needs students had decreased sharply did not tell the full story, Mr Russell argued. "Some of those courses were not delivering for these young people," he said, adding that provision for ASN students was better than before the reforms.
"I think that applies to every young person who comes into the system," he said.
On Scottish independence, Mr Russell acknowledged that attainment levels had risen under devolution. But he insisted that independence was essential "to finish that job", with the Child Poverty Action Group currently predicting 50,000 more children living in poverty in Scotland by 2020.
"We cannot [close the poverty gap in education] because we do not have the fiscal powers," Mr Russell said. "We cannot use taxation, we cannot use labour market regulation, we cannot use welfare. And it's actually worse than that, because.there is a tide running against us in terms of the [Westminster] austerity agenda and welfare cuts."
Next week, TESS interviews Labour education spokeswoman Kezia Dugdale