A série de exercícios tem uma intensidade alta.

A is the feminine singular definite article, meaning the.

It is used because série is a feminine singular noun:

• a série = the series / the set

In Portuguese, nouns usually need an article more often than in English, especially in normal descriptive sentences like this one.

Série here means series, sequence, or set. In the context of exercise, it often refers to a group of exercises or a training set/routine.

A learner might also see:

• uma série de exercícios = a series/set of exercises
• um treino = a workout / training session
• uma sequência de exercícios = a sequence of exercises

So série is perfectly normal here.

Because Portuguese commonly uses de to link one noun to another, much like of in English.

So:

• série de exercícios = series of exercises
• literally: series of exercises

This structure is very common:

• copo de água = glass of water
• aula de português = Portuguese class
• programa de treino = training program

Because the sentence is talking about more than one exercise.

• exercício = exercise
• exercícios = exercises

So uma série de exercícios means a set/series made up of multiple exercises.

Tem is the third-person singular form of ter.

Here, ter means to have:

• A série = the subject
• tem = has

So:

• A série de exercícios tem... = The series of exercises has...

It is tem because the subject is singular: a série.
Even though exercícios is plural, the main noun is série, so the verb stays singular.

Both can be possible depending on style, but uma intensidade alta sounds natural because Portuguese often uses an article with a noun in this kind of statement.

It is similar to saying:

• has a high intensity

The structure is:

• uma intensidade = an intensity
• alta = high

So the full phrase is:

• uma intensidade alta = a high intensity

In Portuguese, adjectives often come after the noun.

So:

• intensidade alta = high intensity
• literally: intensity high

This is one of the most common differences from English word order.

That said, Portuguese sometimes allows adjectives before the noun, but after the noun is the normal default in many cases, especially in straightforward descriptions like this one.

Because alta has to agree with intensidade, which is a feminine noun.

• intensidade = feminine
• therefore the adjective must also be feminine
• alta = feminine singular
• alto = masculine singular

This is called gender agreement.

Compare:

• uma intensidade alta = a high intensity
• um nível alto = a high level

Yes — and in many contexts, that may sound even more natural.

Compare:

• A série de exercícios tem uma intensidade alta.
• A série de exercícios é de alta intensidade.

Both communicate the same basic idea, but the second version is often more idiomatic in fitness or descriptive language.

Why? Because Portuguese frequently uses:

• ser de + noun phrase

So:

• de alta intensidade = of high intensity / high-intensity

This structure is very common:

• um treino de alta intensidade = a high-intensity workout

Because the core noun at the start is série, and de exercícios is just a complement describing what kind of series it is.

So the structure is:

• [A série] = main noun / subject
• [de exercícios] = modifying phrase

That is why the verb is singular:

• A série ... tem not
• A série ... têm

A similar example in English would be:

• The group of students is ready not
• The group of students are ready
  at least in standard singular agreement.

The accent in série shows the stressed syllable and helps mark the correct pronunciation.

It is pronounced roughly like:

• SEH-rie

The stress is on the first syllable:

• SÉ-rie

The accent mark is important because it tells you where the stress goes and distinguishes the word’s standard written form.

It is grammatically correct and understandable, but it can sound a little more formal or descriptive than everyday speech.

In natural Brazilian Portuguese, people might also say:

• A série de exercícios é intensa.
• Essa série é bem intensa.
• A série é de alta intensidade.

So the original sentence is fine, but in casual conversation, shorter versions are often preferred.

Yes. Portuguese often uses the structure de alta intensidade to express that idea.

For example:

• treino de alta intensidade = high-intensity workout
• exercícios de alta intensidade = high-intensity exercises

This is a very useful pattern:

• de + adjective + noun

So instead of building everything with ter, Portuguese often prefers a structure like:

• é de alta intensidade or
• um treino de alta intensidade